Tuesday
February 21, 2017

Posts by STEVE

Total # Posts: 48,677

CAMBRIDGE
Label the points from left to right: A,P,Q,M,B AP = 2x PB = 3x AQ = 3y QB = 4y PQ = 2 AP+PQ=AQ, so AQ-AP=PQ: 3y-2x = 2 PQ+QB=PB, so PB-QB=PQ: 3x-4y = 2 Solving that, we get y=2, so AB = 7y = 14
February 21, 2017

value
http://lmgtfy.com/?q=Concept+Of+Special+Interaction
February 21, 2017

math
twice as many hens can lay twice as many eggs in the same time.
February 21, 2017

Data
There are 15! ways to arrange the balloons. But, the 5 green balloons can be rearranged in 5! ways that appear the same. Same thing for the other colors. So, you end up with 15!/(5!6!4!) = 630,630 ways
February 21, 2017

Pre Calculus 30
#1. 5 choices for each digit. So, 5^4 #2. correct #3. 1 * 4^3 #4. 2^3 * 10^4 when repetitions are allowed, you get more choices...
February 20, 2017

Quantitative Reasoning (MATH)
false the yearly reduction amount decreases with a smaller remaining value.
February 20, 2017

algebra
25750 * 0.8^5
February 20, 2017

Algebra
right track, but you made a mistake right at the start: 6z^2 + 40z - 5 = 0 z = (-40±?(40^2+4*6*5))/12 = (-40±?(1600-120))/12 = (-40±?1480)/12 = (-40±2?370)/12 = (-20±?370)/6 z = -0.127 or -6.539
February 20, 2017

Math
just solve the normal way: C=T/70 +E/30 C + T/70 = E/30 (70C+T)/70 = E/30 E = 30(70C+T)/70 = 3/7 (70C+T) or, E = 30C + 3/7 T
February 20, 2017

Algebra Word Problem
(x-2)(x+2) = 9+12x x = 13 So, the numbers are 11,13,15
February 20, 2017

math (precalc)
complex values come in pairs (why?), so the roots are 3-4i, 3+4i, 5, 5 R(x) = (x-(3-4i))(x-(3+4i))(x-5)^2 = ((x-3)+4i)((x-3)-4i)(x-5)^2 = ((x-3)^2+4^2)(x-5)^2 = (x^2-6x+25)(x-5)^2 = x^4 - 16x^3 + 110x^2 - 400x + 625
February 20, 2017

Pre Calculus 30
#1 First consider all the ways where A&B are together. This is equivalent to permuting 6 students (AB,C,D,E,F,G): 6! = 720. But, we have to double this, since AB and BA are two possible ways that A&B can be together. There are 7! ways to permute the 7 students. 7! - 2*6! = 720...
February 20, 2017

Algebra
well, did you try the values, to see whether they work? 80*(-1.33)^2 - 96(-1.33) + 27 = 296.192 Hmmm. I'd say nope. So, too bad you didn't show your work... 80x2^ - 96x + 27 =0 Using the quadratic formula, since there are so many possible factors of 80 and 27, x = (96&...
February 20, 2017

Algebra
If you meant 2.1/(x+1) + 1 4/5 = 3/(10x) then x = -1±?(7/6) If you meant 2.1/(x+1) + 1 4/5 = 3/10 x (5±?77)/2
February 20, 2017

math 1
a = 2b-8, so (assuming the usual sloppiness with parentheses) 2b-8 = 2/(b-3) (b-4)(b-3) = 1 Now just solve the quadratic. I suspect a typo, just fyi.
February 20, 2017

Algebra
w(3w-2) = 65 5*13 = 65
February 20, 2017

algebra
so if the equations involve c and d, what are x and y? The first equation says c-3d = 27 so, c = 3d+27 Use that in the other equation: 4d+10c=120 first, divide by 2 so you can work with smaller numbers: 2d+5c = 60 Now, since c = 3d+27, that means 2d+5(3d+27) = 60 2d+15d+135 = ...
February 20, 2017

Algebra - rats - and the t!
L2 = (3,7,-11/3) - 4/9 (-3,-3,4)t = (3,7,-11/3) + 4/9 (3,3,-4)t
February 20, 2017

Algebra - oops - lost the n
L2 is (3,7,k) + n(-3,-3,4)t
February 20, 2017

Algebra
L1 is (4,2,-3) + (1,3,-2)t L2 is (3,7,k) + (-3,-3,4)t 4+t = 3-3n t 2+3t = 7-3n t 4+t-3 = 2+3t-7 t = 3 n = -4/9 Now we can see that -3-2t = k+4nt -3-2(3) = k+4(-4/9)(3) k = -11/3 L2 = (3,7,-11/3) - 4/9 (-3,-3,4) = (3,7,-11/3) + 4/9 (3,3,-4) at t=3, L1(3) = (4,2,-3) + 3(1,3,-2...
February 20, 2017

physics
well, it takes 0.4/1.7 = 0.235s to travel that distance. now use your usual equation of motion to find the vertical distance fallen in that time.
February 20, 2017

Algebra/Math
if it's 8% by weight, then .08 * 150 And the wording should be 150g of an 8% solution
February 20, 2017

Math
t = u-2 10t+u + 10u+t = 154 154 = 11*14 so t+u=14 the number is 68
February 20, 2017

Math
try again in English ...
February 20, 2017

math
review your basic trig functions. Draw a diagram. Note that tan? = 12/19 now you can find ?.
February 20, 2017

Math
this is just your classic work problem. You started out right, but then went off into the mists. 1/x = 1/40+1/60-1/80 1/x = 7/240 x = 240/7
February 20, 2017

Math
f = d^2 f+5 = 3(d+5)
February 20, 2017

Math
2(x+8) = 25 Solve for x, then use to get the area. = 8x
February 20, 2017

math
36+x = 3(4+x)
February 20, 2017

value
r^2 = 567/63 = 9 r = ±3 Now you can find a, and S6 = a(r^6-1)/(r-1)
February 20, 2017

Science
20/(60+20) = 1/4
February 20, 2017

Chemistry
.28 * 6.023 * 10^23 * 2
February 20, 2017

Algebra
well, 2 days = 48 hours, so ...
February 20, 2017

Calculus
#1 swap variables and solve for y: x = ?(3y-2) x^2 = 3y-2 y = (x^2+2)/3 now f(x) has domain: x >= 2/3 range: y >= 0 f^-1(x) has domain: x >= 0 range: y >= 2/3 because f(x) has only one branch #2 f(x) = ?[1,x] sin(t)/t dt I don't think you want f(x), because it ...
February 19, 2017

Math 104
5P2 = ?
February 19, 2017

math
(2,3) [2,3]
February 19, 2017

Algebra2
write a recursive formula for the sequence 5,18,31,44,57 then find the next term. My answer is a1=5,an=an-1+13 The next term would be 70.
February 19, 2017

Calculus II
google the topic and you will find many discussions and examples. For a region of uniform density, the center of mass is the same as the centroid.
February 19, 2017

Pre-Calculus
3 = 2.1 sin[(?/6)t - 5?/6] + 3.2 2.1 sin[(?/6)t - 5?/6] = -0.2 sin[(?/6)t - 5?/6] = -0.095238 (?/6)t - 5?/6 = -.0953826 (?/6)t = 2.522611 t = 4.8178 and of course, there is another solution
February 19, 2017

Math
9.50a + 5.50(148-a) = 1170.00
February 19, 2017

Algebra2
thank you
February 19, 2017

Algebra2
cd = k a constant. So, you want d such that 86d = 2*17
February 19, 2017

Algebra2
suppose c and d vary inversely and d=2 when c=17 write an equation that models that variation find d when c=68
February 19, 2017

Algebra2
note that xy = 10
February 19, 2017

Algebra2
Does the relation in the table represent direct variation, inverse variation, or neither? if it is direct or inverse variation, write an equation to represent the situation. Explain your answer x 5, 10, 15, 20 Y 2, 1, 2/3, 1/2
February 19, 2017

MATH
15/(10+15) = 3/5 = 60%
February 19, 2017

Maths bearing
use the law of cosines.
February 19, 2017

Math
use the law of cosines.
February 19, 2017

Math
I'd guess the same, if it's in the same circle ...
February 19, 2017

Differential equation
?? Just plug in the numbers: at r=3, dr/dt = 5?/36 = k/9 k = 5?/4
February 19, 2017

Math
since 1 revolution is 360 degrees, (25 * 2? ft/rev) * (2?/10 rev/s) * 3600s/hr * 1mi/5280 ft = 10.71 mi/hr
February 19, 2017

Math
looks like it already is!
February 19, 2017

math
subtract the area of the lawn from the total area including path: (50+16)(40+16)-50*40 = ?
February 19, 2017

fractionss
2/3 * 1/2 ordered dessert
February 19, 2017

fractions
the amount left was (1 - 4/7)(1 - 2/5) = 3/7 * 3/5 = 9/35 of the original amount. So, 9/35 x = 9 x = 35
February 19, 2017

Differential equations
yes indeed
February 19, 2017

Maths
3*2*(120+68) = 1128m
February 19, 2017

math
read this and follow the example. What do you get? Hint: the curve looks like a straight line to me ...
February 18, 2017

Math
hard to say, with no diagram and no description...
February 18, 2017

Math
.60*70 + x*40 = .70*110 x = .875 so, they must win 7/8 * 40 = 35 of the remaining games. Good luck with that...
February 18, 2017

math
x=1, so A=1+2+1 = 4 ...
February 18, 2017

Math
-1/8 (x+35)= -7 x+35 = -7(-8) = 56 x = 21
February 18, 2017

calculus
E = IR dE/dt = R dI/dt + I dR/dt If E is constant, then dE/dt = 0 if R=20, then I = 5, so you can use that in the formula above. Naturally, if R is increasing, the current is decreasing.
February 18, 2017

physics
geez - you have the equation - plug in the numbers.
February 18, 2017

math
D is the lateral area. If you include the base, then you get choice B
February 18, 2017

algebra
y(x(t)) = ln(2x(t)) = ln (2*3e^(t/1.7)) = ln6 + ln e^(t/1.7) = t/1.7 + ln6
February 18, 2017

Algebra
google is your friend. This is but one of many discussions on the topic. http://www.web-formulas.com/math_formulas/geometry_surface_of_cone.aspx
February 18, 2017

science
resistance = (resistivity * length)/area so, just plug in your numbers... watch the units.
February 18, 2017

Math
That's what I get, too.
February 18, 2017

science
You need 2 H for each CO3, so 2HCl + K2CO3 -> 2KCl + H2CO3
February 18, 2017

electronic
sounds like you just have to plug in the numbers ...
February 18, 2017

MATH
As Crocodile Dundee would say, Now that's a detour! (eh?)
February 18, 2017

MATH
cosA = 1/2 A = ?/3 4A = 4?/3 cos4A = -1/2
February 18, 2017

Science
NO is 2/5 of the output of 10 moles. Since the original 9 moles occupied 27 liters, the 10 moles occupy 30 liters. So, NO occupies 2/5 * 30 = 12 liters. This assumes that the H2O is also a vapor.
February 18, 2017

Algebra
2x+2y = 28 so, y=14-x for the area, a = xy = x(14-x) This is just a parabola,so find its vertex.
February 17, 2017

Math
what were the possible scores on the dart board?
February 17, 2017

Math
yes.
February 17, 2017

Physics
23 * 24 * 8/1000 = 4.4¢
February 17, 2017

um
at wolframalpha.com, type in arctan(8) Or, learn to use your calculator ...
February 17, 2017

precalculus
e^(.08t) = 2 The initial amount does not matter.
February 17, 2017

geometry
in a 30-60-90 right triangle, the ratio of the sides is 1:?3:2 m?L = 30°, so the short leg is 9. The sides are thus 9,9?3,18 and the perimeter is 27+9?3 Looks like you need to review the standard triangles...
February 17, 2017

geometry
note that in a 45-45-90 right triangle, the sides are in the ratios 1:1:?2 So, draw the figure, label the known side, and then you can get the others.
February 17, 2017

physical science
more likely, something metric ...
February 17, 2017

Esol
correct.
February 17, 2017

math
uh, I'd guess 20/8
February 17, 2017

Algebra
f(x) = -5(3^x) f(0) = -5(3^0) = -5(1) = -5 f(1) = -5(3^1) = -5(3) = -15 f(2) = -5(3^2) = -5(9) = -45 the graph is at http://www.wolframalpha.com/input/?i=-5(3%5Ex)
February 17, 2017

Geometry
PN^2 = 17^2-15^2 = 64 PN = 8 So, NQ = 39-8 = 31 QR^2 = 31^2+15^2 = 1186 QR = 34.438
February 17, 2017

Math
Alkesh borrowed -- x Sanjay borrowed -- 2x So, how much interest did Sanjay pay? see where that takes you. (I think the actual question is garbled...)
February 17, 2017

math
A = ?ab Note that for a circle, a=b, so A = ?a^2
February 17, 2017

math
dy/dt = y/4 dy/y = 1/44 dt lny = t/4 + c y = c*e^(t/4) y(0)=20, so c*e^0 = 10 c = 20 y = 20e^(t/4) You are correct.
February 17, 2017

Geometry
since the diagonals bisect each other, AE = EC 3x+12 = 27 ...
February 17, 2017

Vector
Assuming it is in the same direction, then if p is the vector to P, then p+v = [-11,-1] Q = (-11,-1) Q could also be the end point of p-v.
February 17, 2017

math
"more" means you are going to add. Add what to what?
February 17, 2017

Math
4.75 = 4 3/4 = 19/4 6 1/8 = 49/8 6.3 = 63/10 10 1/2 = 21/2
February 17, 2017

Stat
2(26^2 + 26^3) = ?
February 17, 2017

Algebra
(x-1/2)-(x-2/2)+(x-3/2)-...-(x-100/2) x-x+x-x+...+x-x - 1/2 + 2/2 - 3/2 + ... - 99/2 + 100/2 the x-x+x-x terms cancel out, and we are left with 1/2 (-1+2 -3+4 ... -99+100) = 1/2 (1+1...+1) (50 times) = 1/2 * 50 = 25
February 17, 2017

Maths
first, how is the "rank" of a word defined?
February 16, 2017

Math
$22/player, so ...
February 16, 2017

Statistics
You can play around with Z table stuff here: http://davidmlane.com/hyperstat/z_table.html
February 16, 2017

math
using similar triangles, if he is x meters from the tree, (x+3.5)/28 = 3.5/1.5
February 16, 2017

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