Saturday
January 21, 2017

Posts by Reiny

Total # Posts: 37,345

Math
no, why would you divide by 3? you correctly converted the square feet to square yards by dividing by 9, and your cost was in square yards. your cost is $610.50
December 14, 2016

precalculus
http://www.jiskha.com/display.cgi?id=1481565350
December 14, 2016

algebra
well, first lets get rid of those nasty fractions ... multiply the first by 10 6x = 5y + 110 or 6x - 5y = 110 ** 3x + 8y = 13 <--- I assume yours was a typo double the 2nd: 6x + 16y = 26 *** subtract *** from ** -21y = 84 y = -4 sub back into 3x+8y=13 to find x
December 14, 2016

Math - Algebra (Percents and Ratios)
number of people in stands --- x number who were parents = (3/4)x) of those 4/7 were moms total moms = (3/4)(4/7)x = (3/7)x percentage of moms = (3/7)x / x = 3/7 = appr 43%
December 14, 2016

algebra
I will show you the first one .... ?50 = ?25*?2 = 5?2 general method: Factor your number so that one or more factors are perfect squares. e.g. ?720 = ?9*?16*?5 = 3*4*?5 = 12?5 Show me what you did for the 2nd question
December 14, 2016

pure math
Did you mean (1 - x/2)^(1/5) ? Are you studying the binomial theorem?
December 14, 2016

math
You are welcome
December 14, 2016

math
Yes, it would be because of the repeated multiplication by .88 suppose we show a few steps after 1 km : Pr = 1013(.88) after 2 km : Pr = 1013(.88)(.88) = 1013 (.88)^2 after 3 km : Pr = 1013(.88)^2 (.88) = 1013 (.88)^3 etc , for after x km : Pr = 1013 (.88)^x
December 14, 2016

One step inequalities
x - 9 ? 27
December 14, 2016

precalculus
Steve had done the above steps for you, see the first of the Related Questions for you. First, it might help if you looked at the graph http://www.wolframalpha.com/input/?i=polar+plot+r%3D8cos(3%C3%98) Steve told you: |cos 3Ø| ? 1 so |8cos 3Ø| ? 8 | r | ? 8 , so ...
December 14, 2016

Math
Take a small rectangular piece of paper, such as a business card, hold a finger on the end of the longer side and rotate the card. What do you notice ?
December 14, 2016

Probability
first of all listing the choices of digits 444 --- can be arranged in 1 way 442--- can be arranged in 3 ways 443--- can be arranged in 3 ways 422--- can be arranged in 3 ways 433--- can be arranged in 3 ways 423--- can be arranged in 6 ways 222--- can be arranged in 1 way 223...
December 14, 2016

Math
weight of empty basket --- x weight of 1 pear ---------- y x + 30y = 11.2 x + 18y = 7 subtract them: 12y = 4.2 y = .35 sub back: x + 18(3.5) = 7 x = 4.2 Each pear weighs 350 g and the basket ways 4.2 kg so basket with 7 pears = .......
December 14, 2016

maths
total expenses = 2030+4900+3150 = .... so 2x + 3x + 4x = total above find x, sub back into 2x, 3x, and 4x
December 14, 2016

Algebra
Athena's age is expressed as a function of the cousin's age, so it is usually easier to define the domain Four years ago: let the cousin's age be x then Athena was 2x-5 present: cousin ---- x+4 Athena ----- 2x-5 + 4 or 2x - 1 x+4 = 3(2x-1) - 18 x+4 = 6x - 3 - 18 25...
December 14, 2016

maths
done http://www.jiskha.com/display.cgi?id=1481713097
December 14, 2016

Math
Prob(a 6) = 1/6 , prob(not a 6) = 5/6 so in 5 tosses you want that 3 times Prob(of your event) = C(5,3) (1/6)^3 (5/6)^2 = 10(1/216)(25/36) = 125/3888 or appr .03215
December 14, 2016

precalculus
Steve said: http://www.jiskha.com/display.cgi?id=1481636669 and this: http://www.jiskha.com/display.cgi?id=1481653351 Make use of it please
December 13, 2016

business
amount = 2000 ( 1.05^40 - 1)/.05 = ....
December 13, 2016

math
hina gets ---- x rina gets ----- 3x - 100 x + 3x-100 = 300 4x = 400 x = 100 Hina would get 100 and rina would get 3(100) - 100 or 200
December 13, 2016

precalculus
umhh, what part of the solution I gave you yesterday did you not like? http://www.jiskha.com/display.cgi?id=1481597953
December 13, 2016

I THINK I FIGURED IT OUT!
Another simple way to look at it: 24 ----> 6 , so it was reduced by a factor of 1/4 what is (1/4) of 18 ????
December 13, 2016

I THINK I FIGURED IT OUT!
NOPE, look at my last reply to your previous post
December 13, 2016

a.p.
ok, your turn use your definitions
December 12, 2016

a.p.
terms are a, a+d, a+2d, a+3d 4a + 6d = 4 2a + 3d = 2 ---> a = (2-3d)/2 a(a+3d) + (a+d)(a+2d) = -38 a^2 + 3ad + a^2 + 3ad + 2d^2 = 38 2a^2 + 6ad + 2d^2 = -38 2(4 - 12d + 9d^2)/4 + 6d(2-3d)/2 + 2d^2 = -38 (4 - 12d + 9d^2)/2 + 6d(2-3d)/2 + 2d^2 = -38 times 2 4 - 12d + 9d^2 + ...
December 12, 2016

a.p.
sides must be a, a+d, and a+2d a^2 + (a+d)^2 = (a+2d)^2 a^2 + a^2 + 2ad + d^2 = a^2 + 4ad + 4d^2 a^2 - 2ad - 3d^2 = 0 (a - 3d)(a+d) = 0 a = 3d or a = -d case 1: a = 3d let d = 1 then a = 3 , and the sides are 3, 4, and 5 let d = 2 then a = 6, and the sides are 6, 8, and 10 ...
December 12, 2016

math
what is 7x8x4 ?
December 12, 2016

Algebra PLEASE HELP ME
BC = 11 - (-2) = 13 what is the difference between a height of 8 and a height of 20 ?? Did you look at your diagram?
December 12, 2016

Algebra PLEASE HELP ME
slope of BC = (8-8)/(11=2) = 0 so BC is a horizontal line Thus the line through A must be a vertical line All vertical lines have the form x = something Look at the given point A, what is its x value ? so the equation of your required line is x = 3 Make a sketch. The base BC ...
December 12, 2016

Math lovely Math
prob(elephant) = 7/20 prob(tiger) = 6/20 continue ... add them up to make sure they add up to 1, they will! If they don't you messed up
December 12, 2016

Math
arc = rØ, where Ø is in radians 25 = 7Ø Ø = 25/7 radians
December 12, 2016

Math
cost per hour = 175/5 = 35 (not bad for babysitting, but then again I haven't needed a babysitter in 70 years) cost = 35t , where t is the number of hours slope is 35 y-intercept is 0 It is a proportion, and it is a function
December 12, 2016

h.p.
The base of your powers is an arithmetic sequence sum(1) = 1 sum(2 ) = 1+ 4^2 = 17 sum(3) = 17 + 7^2 = 66 sum(4) = 66 + 10^2 = 166 sum(5) = 166 + 13^2 = 335 sum(6) = 335 + 16^2 = 591 ... with the third difference column of 18, we know it must be in the form of a cubic we could...
December 12, 2016

math
32/9 = 3 5/9 you will have to guess at the 5/9, since your numberline probably has divided the unit in tenths, not ninths so between 3 and 4 , just a bit more than half way between 3 and 4
December 12, 2016

Pre-Calculus
I don't see "the following function"
December 12, 2016

precalculus
form y = (3/2)x b:a = 3/2, but a = 3 b/3 = 3/2 2b = 9 b = 9/2 hyperbola: x^2 /9 - y^2/(81/4) = 1 or x^2/9 - 4y^2/81 = 1 or 9x^2 - 4y^2 = 81 whichever form your text considers standard form
December 12, 2016

Calculus
first number --- x 2nd number ----y 3rd number ---- 40-x-y x + 3y + 4(40-x-y) = 80 x + 3y + 160 - 4x - 4y = 80 -3x- y = -80 3x + y = 80 y = 80-3x product = x(y)(80-x-y) = 80xy - x^2 y - x y^2 = 80x(80-3x) -x^2(80-3x) - x(6400 - 480x + 9x^2) = .... = 160x^2 - 6x^3 d(product)/dx...
December 12, 2016

Math Help
First of all you don't have an equation, so "cross-multiplication" is a meaningless term. You did not match up the corresponding numbers, which was my whole point, and objection to this question your equation should have been: 24/6 = 18/x or 6/24 = x/18 <--- I...
December 12, 2016

Math Help
Show me the steps that gave you 72, as I said, I got 4.5 x : 18 = 6 : 24 <-- following corresponding pattern x/18 = 6/24 24x = 108 x = 108/24 = 4.5
December 12, 2016

Math Help
It is not a matter of choosing an answer. You must determine the answer with some solution. Why did you "choose" that answer? I would assume that the sides are listed in the corresponding order. In that case none of the answers given are correct. I got x = 4.5
December 12, 2016

Calculus
Since (1-2x-3x^2)/(1+x) = (1+x)(1-3x)/(1+x) = 1 - 3x, x ? - 1 what do you think you should use
December 12, 2016

Algebra
I divided the 2nd equation by 2 to get the x terms to be both 5x Are you not familiar with the method of elimination? Just like we can multiply each term of an equation by some number, we can also divide each term by some number without changing the value of the equation. (...
December 12, 2016

math
?x - 6 = x^(1/4) let ?x = t then we have t - 6 = ?t square both sides t^2 - 12t + 36 = t t^2 - 13t + 36 = 0 (t-9)(t-3) = 0 t = 9 or t = 3 if t = 9, then x = 81 if t = 3, then x = 9 since we squared our equation, all answers must be verifies if x = 81 LS = ?81 - 6 = 9-6 = 3 RS...
December 12, 2016

Algebra
1000 e^(kt) = 1274 e^(5k) = 1.274 take ln of both sides 5k = ln 1.274 k = ln 1.274/5 = .048323... = 4.83 % rounded to the nearest hundreth
December 12, 2016

Math
y = 1500 (1.071)^t , where t is in hours
December 12, 2016

Math
As Steve already did this for you, I don't know why you are repeating it. ... Anyway, prob(of your event) = (3/10)(5/10) = 15/100 = 3/20 , which is what Steve had told you.
December 12, 2016

Math
number for Mr Jones ---- x number for Mr Smith ---- x-500 .03x = .05(x-500 .03x = .05x - 25 -.02x = -25 x = 1250 Mr. Jones sold 1250 widgets and Mr. Smith sold 750 check: .03(1250) = 37.5 .05(750) = 37.5
December 12, 2016

precaculus
no, tanØ = -1 , not Ø = -1 since (2,-2) is in quadrant IV, Ø = 315° or 7?/4 so one answer is (2?2 , 7?/4) another would be (-2?2, 3?/4)
December 12, 2016

Algebra
by definition, |anything| ? 0 so |1-4k| must surely be ? -11 for anything inside the absolute value sign
December 12, 2016

pre-calculus
length --- l width ----w 2l+2w=36 l+w = 18 l = 18-w area = lw = w(18-w) = 18w - w^2 d(area)/dw = 18-2w = 0 for a max of area 2w = 18 w = 9 then l = 18-w = 9 so the area of the base of the box must be a square, 9 by 9 as you probably expected.
December 12, 2016

pre-calculus
let the length be l let the width be w so 2l + 2w = 36 l + w = 18 l = 18-w area = wl = w(18-w) = 18w - w^2
December 12, 2016

precalculus
x^2 - 16 = 4y^2 or (x+4)(x-4) = 4y^2 let x = t then t^2 - 16 = 4y^2 y^2 = (t^2 - 16)/4 y = ± ?(t^2 - 16)/2 , -4 ? t ? 4
December 12, 2016

Calculus
http://www.jiskha.com/display.cgi?id=1481558182
December 12, 2016

Algebra
Surely you can follow the method I just showed you in your previous question almost identical to this one. Did you even look at my answer ?
December 12, 2016

algebra
double the 2nd: 5x + 6y = 24 now sub the first one into that 5x + (-5x + 24) = 24 5x - 5x + 24 = 24 0 = 0 , which is a true statement, thus you have an infinite number of solutions.
December 12, 2016

Calculus
Consider it as the points (1,-4), (2,-4), (3,-3) etc let the function be ax^2 + bx + c = y for: (1,-4) ---> a + b + c = -4 * (2,-4) ---> 4a + 2b + c = -4 ** (3,-3) ---> 9a + 3b + c = -3 *** subtract * from ** 3a + b = 0 # subtract ** from *** 5a + b = 1 ## subtract # ...
December 12, 2016

Calculus
Just do it. I am sure you can subtract.
December 12, 2016

precalculus
I would leave the y value in exact form y = r sinØ = -14(?3/2) = -7?3 you also missed the negative sign in your y value exact point (-7, -7?3)
December 12, 2016

pre calculus
correct: http://www.wolframalpha.com/input/?i=parametric+plot+x%3Dt+,+y%3Dt%5E2%2B10 http://www.wolframalpha.com/input/?i=parametric+plot+x%3Dt%5E3,++y%3Dt%5E6%2B10
December 12, 2016

Calculus
intersection of y = 12 and y = e^x e^x = 12 x = ln 12 area = ?(12 - e^x)dx from 0 to ln12 = [12x - e^x] from 0 to ln12 = 12ln12 - e^(ln12) - (0 - e^0) = 12ln12 - 12 - 0 + 1 = 12ln12 - 11 http://www.wolframalpha.com/input/?i=area+between+y+%3D+e%5Ex,++y+%3D+12+from+0+to+ln12
December 12, 2016

precalculus
I think they want you to use a separate graph for each of the values of n to show what happens to the graph as n changes. Wolfram might be of help here: Just change the values in front of the 2nd term to see how it affects the graph. I have shown the graph for n = 3 http://www...
December 12, 2016

quick question regarding math
If your equation has the solution of all real numbers, then your equation is an "identity". here are the different cases for linear equations: case 1: one unique solution 3x -4 = 2x + 1 3x-2x = 1+4 x = 5 case 2: no solution 3x - 4 = 3x - 5 3x-3x = -5+4 0 = -1 , which...
December 12, 2016

Math
Not familiar with the notation A^BC for an angle The usual notation is angle ABC, where B would be the vertex of the angle and the containing sides would be AB and BC Explain your notation.
December 12, 2016

Math.
14x?1/2(4x+6)=3(x?4)?18 14x - 2x - 3 = 3x - 12 - 18 I am sure you can take it from here.
December 12, 2016

math
200000000 or 200,000,000 would be "two hundred million"
December 12, 2016

Math
The areas of similar objects are proportional to the square of their corresponding sides. so 28 : x = ?8 : ?25 28/x = 2?2/5 2?2x = 140 x = 70/?2 or 35?2
December 12, 2016

Mathematics
5 women 7 men, choose 4 a) number of ways with no restriction = C(12, 4) = 495 b) must be 3 men and 1 woman = C(7,3) x C(5,1) = 35 x 5 = 175 c) at least 3 women ---> 3 women or 4 women = C(5,3) x C(7,1) + C(5,4) x C(7,0) = 10x7 + 5x1 = 75
December 12, 2016

math
let the sides be 3x, 4x, and 5x 3x+4x+5x = 24 12x = 24 x = 2 sub back into my definitions of the sides so the sides are 6, 8, and 10
December 12, 2016

math
Question makes no sense!
December 11, 2016

algebra
(9/10)x + 1/x = x times 10 9x + 10/x = 10x times x 9x^2 + 10 = 10x^2 x^2 = 10 x = ?10 check: 1/?10 = 1/?10 *?10/?10 = ?10/10 so (9/10)?10 + 1/?10 = (9/10)?10 + ?10/10 = 10?10/10 = ?10
December 11, 2016

Algebra
don't make it so complicated, all you want is the coefficients of either the x's or the y's to be the same. 3x +6y = $48.00 , divide by 3 --> x + 2y = 16 2x + 8y = $46.00 , divide by 2 --> x + 4y = 23 subtract them: 2y = 7 y = 3.5 then in x+2y = 16 x + 7 = 16...
December 11, 2016

Algebra
After a proper definition of your variables, your system is correct to solve, how about multiplying the first by 2, and then subtracting them ? I am sure you can take over from here
December 11, 2016

Pre-Calculus
I don't know what procedure you learned, but this is how I taught this: step 1: show it to be true for n = 1 LS = 3 RS = 1(4-1) = 3 step 2: assume it is true for n = k that is 3+11+19+..+ (8k-5) = k(4k - 1) step 3: show it then must be true for n = k+1 that is, show 3+11+...
December 11, 2016

MAth
Ms Sue is correct to state that the mathematical probability is 1/2 But according to the "experimental" data of the hospital, it would be 50/90 or 5/9 Silly question!
December 11, 2016

Geometry
nope, 382 is not a side of a similar triangle see my reply to your question when you posted it earlier.
December 11, 2016

math
see http://www.jiskha.com/display.cgi?id=1481507804
December 11, 2016

Algebra!
number of adult tickets --- x number of student tickets -- 2x 7x + 4(2x) = 45 15x = 45 x = 3 so they bought 3 adult tickets and 6 student tickets. check: is the number of adult tickets half of the student tickets ? YES what is the cost: 7(3) + 4(6) = 45 my answer is correct
December 11, 2016

Geometry Honors
Make a sketch and use a simple ratio: 22/h = 40/(40+382) 40h = 22(40+382) = 9284 h = 232.1 ft
December 11, 2016

Algebra
for 1st line: two points are (-3/2, 0) and (0,3) slope = (3-0)/(0+3/2) = 3/(3/2) = 2 so equation of 1st line is y = 2x + 3 2nd line: slope = 3(2) = 6 y intercept = 3 + 28 = 31 equation of 2nd line: y = 6x + 31 intersection: 6x + 31 = 2x+3 4x = -28 x = -7 then y = 2(-7) + 3 = -11
December 11, 2016

Calc
length of pool --- x width of pool -----y cost = 10x + 5y = 1000 2x + y = 200 y = 200-2x area = xy = x(200-2x) = 200x - 2x^2 d(area)/dx = 200 - 4x = 0 for a max of area 4x=200 x=50 then y = 200-100 = 100 state your conclusion
December 11, 2016

math
Snowball was in the air as long as h > 0 let's see when h = 0 0 = -16t^2 + 48t + 28 divide by -4 4t^2 - 12t - 7 = 0 (2t + 1)(2t - 7) = 0 so t = -1/2 or t = 7/2 but t ? 0 so the ball was in the air for 7/2 or 3.5 seconds
December 11, 2016

algerbra
Are you saying: 11?(37x) = 44?37 ???? if so, then ?(37x) = 4?37 square both sides: 37x = 16(37) x = 16
December 11, 2016

math
number of 2-pointers ---- x number of 3-pointers ----- 16-x 2x + 3(16-x) = 38 solve for x
December 11, 2016

algebra word problem
lower rate ---- r higher rate ---- r+.015 1100r + 1800(r+.015) = 288 1100r + 1800r + 27 = 288 2900r = 261 r = .09 the one rate was 9% , the other 10.5% check: 1100(.09) + 1800(.105) = 288
December 11, 2016

Math
2.52 cm = .0252 m
December 11, 2016

Maths
So, one is chose, leaving 14 others to those from. Number of ways = C(14,3) = 364
December 11, 2016

math
the volume of similar objects is proportional to the cube of their corresponding sides, so V1 : V2 = 1^3 : 3^3 V1 / 162 = 1/27 V1 = 162/27 = 6 the new volume is 6 cm^3
December 11, 2016

Algebra
let the first be x let the second be y the third is x-45 x+y > x-45 by 80 ---> x+y = x-45 + 80 x + y = x + 35 y = 35 x + y + x-45 = 194 2x + 35 - 45 = 194 2x = 204 x = 102 the first is 102 the 2nd is 35 the 3rd is 57
December 10, 2016

Algebra
9|r-2|-10<-73 9|r-2| < -63 |r - 2| < -7 BUT, the absolute value of anything has to be ? 0, so it certainly cannot be ? -7 Your inequation has no solution. Just try some numbers in your solution, they don't work. e.g. for r < 9 , let r = 4 LS = 9|4-2) - 10 = 8 ...
December 10, 2016

geometry
compare the two lengths of the corresponding dimenstions: lengths: 14.7/4.2 = 3.5 widths : 20.3/5.8 = 3.5 heights: 33.6/9.6 = 3.5 well, how about that ??
December 10, 2016

Algebra
Something not right here. According to your equation, it is not launched from ground level, but from a height of 4 units. Furthermore it is launched with a downwards velocity of 1 unit of distance/ 1 unit of time domain: t ? 0 check for a typo
December 10, 2016

Algebra
see my comment at your repeat posting of the same question above.
December 10, 2016

Algebra
First of all , don't switch to decimals ( 7/6 ? 1.16, it is 1.1666.... ) So you have two points (-7/6 , 0) and (0,7) slope = (7-0)/(0+7/6) = 7/(7/6) = 6 equation of first line : y = 6x + 7 slope of 2nd line = 12 <----- it said twice the first y-intercept of 2nd line = 7...
December 10, 2016

Algebra
First of all , define your variables 3x + 7y = $46.00 8x + 4y = $75.00 <----- notice correction 3x + 7y = $46.00 (times 8): 24x + 56y = 368 8x + 4y = $75.00 (times 3): 24x + 12y = 225 subtract them: 44y = 143 y = 3.25 go back into one of the original equations to find x, ...
December 10, 2016

Algebra
equation #1: x - y = 47 equation #2: deals with the number of legs 4x + 2y = 938, or 2x + y = 469 add our two equations: 3x = 516 take over....
December 10, 2016

Maths
now: Mona ---- x Dad ----- 3x in 12 years: Mona = x+12 Dad = 3x+12 3x+12 = 2(x+12) take over
December 10, 2016

Algebra
Why do you have L's, W's and x's in your equation ? width ---- w length ---- l equation #1: 2w + 2l = 84 w+l = 42 ** equation #2: "The length of a rectangle is 91 less than six times the width of the rectangle" ---> l = 6w - 91 sub that back into ** w...
December 10, 2016

MATH
so a point on it is (4,0) y-0 = 3(x-4) y = 3x - 12
December 10, 2016

math
so it must be a vertical line All vertical lines have equation of the form x = c, where c is a constant look at the point (3,-1) , its x value is 3 so : x = 3 is the equation.
December 10, 2016

V.i.p. Maths
Bob, I always thought that happened in Indiana. https://en.wikipedia.org/wiki/Indiana_Pi_Bill 22/7 is the best approximation to ? using at most 2 digits as the numerator of the fraction. If you allow 3 digits, the best fraction is 355/113 which differs from ? by only ....
December 10, 2016

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