# Posts by steve

Total # Posts: 54,320

Maths
the length x of the hill is found via 30/x = sin35° you can take it from there, right?

Math
The length of the road is the perimeter of the field. So the cost to plant it is perimeter*cost/meter: 2(45+35)*15 Of course, that is the length of the inside of the road. If the trees are planed more toward the outside, then the length will be greater...

math
y^-4 = 1/y^4

Computer
nope

Math
-1/2 - 3/4 = -6/12 - 9/12 = -15/12 = -4/3 So, you have a typo. -1/2 + 3/4 = 3/12 = 1/4 Using 1/2 and 3/4 you cannot get any of the choices.

Math
correct. As is -2^4 = -16

Math
(x)^3 is exactly the same as x^3 (-2)^3 = (-2)(-2)(-2) = -8 -2^3 = -(2)^3 = -(2*2*2) = -8 works ok for odd powers, but not for even ones.

Math
the area of the path is the total area minus just the pool. Since the path is 2m wide, the radius of the whole is 22m. So the area of just the path is ?(22^2-20^2) = 84? m^2

Math
g(f) = (f^2+2)/f = ((?x+3)^2+2)/?(x+3) = (x+5)/?(x+3)

Math
the axis of symmetry is the line x=5 So, any domain on one side of that line will be one-to-one. Now, for the inverse, swap variables and solve for f^-1 x = (f-5)^2+2 x-2 = (f-5)^2 f-5 = ±?(x-2) f = 5±?(x-2) Now, we need one branch only, but ?(x-2) is only ...

Algebra
y = 15250 * 0.925^x

Math
I see spelling is also definitely on the list of troubles. :-)

Math
Nope. Try A. You need both addition and multiplication. Better review the topic 6.48 = 6 + 0.4 + 0.08

algebra 2 - minimum or maximum
recall that the vertex of the parabola ax^2+bx+c is at x = -b/2a So, your maximum is at x = 4/.5 = 8 now just find f(8)

math
The digit in the ten thousands place is greater than 7 9xxxx The sum of all five digit is 18.The greatest digit is equal to the sum of the other four digits. 94320

Algebra 1
It could also be written as -8n+5v 5v-8n

physics
recall that s = vt + 1/2 at^2 The total distance is thus .98*9.3 + .98*1.8 - 0.11/2 * 1.8^2

euros = dollars * 6/5

math
100

Math
they are the basic trig functions (and that's tangent, not tangine)

Geometry
Hmmm. I think you also need a compass, if you don't trust the protractor.

math
the 100th, since LCM(20,50) = 100

Math
S/M = 2/11 Now just find M for the various values of S.

beginning algebra
2c*3d = 6cd there are 25 cents in each quarter, so in q quarters, there are 25q cents 0.25q is the number of dollars in q quarters.

Math
-3 * (-1 7/12) - (-3/2)^2 = -3*(-19/12)-(9/4) = 19/4 - 9/4 = 10/4 = 5/2

Math
7077 = 360*19 + 237 ...

algrebra hellllllllp!!!!!!!!!!!!!! me plzzzzz
you could always try using math symbols instead of words, as a start. It appears you mean -12/3*(-8+(-4)^2-6)+2 Inside each group of parentheses, do powers, then multiply/divide, then add/subtract. So, step by step we get -12/3*(-8+(-4)^2-6)+2 -12/3*(-8+16-6)+2 -12/3*(8-6)+2 -...

Chemistry
157km * 1mi/1.61km * 1gal/28mi * 3.785L/gal = 13.18L

chemistry
59.0 mL of a 1.60 M solution is diluted to a total volume of 268 mL The volume is increased by a factor of 268/59. So, the concentration is reduced by that factor. 59/268 * 1.60 = 0.3522M Now the volume is increased by a factor of 307/134, so the concentration is reduced by ...

Math
(x-43)(x+42)

COLLED
go look at such a machine. What do you see?

computer application
for i = 100 to 0 step -2 ; print i; assuming you don't want to go on forever with the negative ones ...

Math
You have 4 equations in 4 unknowns, so use elimination or substitution. For example, a+0+h+m = 72 a+c+h+0 = 80 0+c+h+m = 61 a+c+0+m = 57 subtract #1 from #2 and #4 a+0+h+m = 72 0+c+0-m = 8 0+c+h+m = 61 0+c-h+0 = -15 subtract #2 from #3 and #4 a+0+h+m = 72 0+c+0-m = 8 0+0+h+2m...

College Algebra
C(x) = 9000 + 1.20x R(x) = 3.00x now just find x where C=R

College Algebra
Just write the info in math. If \$x is invested at 6%, then .09*3x + .06x = 1980

Math
If there are \$x at 7% then the rest (14000-x) is at 11%. So, adding up the interest, you have .07x + .11(14000-x) = 1220

College Algebra
If there are x gallons of 13%, then the rest (40-x) is 23%. So, adding up all the disinfectant, you have .13x + .23(40-x) = .20*40

Math
see related questions below, or the mixture problems posted after this one.

Math
see the related questions below, or the mixture problems posted after this one.

Math
just add up the values of the coins. If there are d dimes, then 5(d+5) + 10d = 115

Math
see related questions below, or the coin problems posted after this one.

Algebra
see related questions below, or the mixture problems posted after this one.

mr hunt wishe to enclose his goat in a wire fence
so, is 3*7.9 + 4.075 <= 25 ?? Hint 21+4 = 25

Trig
Assuming that Mack is looking at Joey's feet, draw a diagram. It should be clear that if the tree's height is h, then h/25 = tan 53°51" Now just get out your calculator...

Pre Calculus
Recall that Matrix multiplication is always commutative if ... ... one matrix is the Identity matrix. ... one matrix is the Zero matrix. ... both matrices are 2×2 rotation matrices. (basically case #2) ... both matrices are Diagonal matrices.

Math
multiply/divide before add/subtract. So, you really have (55÷11)+7*(2+14)

Pre Calculus
can you skip the LaTex? It appears that you are saying that w = (2,1) and there is a 2x2 P such that w•v = Pv or something like that. Correct?

Pre Calculus
If MA = I, then A = M-1 Can you do matrix inverses?

Algebra
If x kg are added, then we have .55*160 + 1.00x = .70(160+x)

PreCalculus
(f-g)(x) is just f(x)-g(x). That is easy enough: f(x)-g(x) = (x^2+3x-1)-(x^3+4x^2+1) = -x^3 - 3x^2 ...

Maths
each cm is 0.01 meters, so you have 17m + .80m = 17.80m

math
if their ages today are a and b, then we have a = b+9 a-5 = 1.5(b-5) b+9-5 = 1.5b - 7.5 11.5 = .5b b = 23 so, a=b+9=32 (a+4)+(b+4) = 36+27 = 63

math
If the amounts invested are a and b, we are told that 1200(1.20)^2 = b(1+.15*3) + 42 b = 1162.76 Now you ask what percent is B of "that". No idea what you mean, but if you want the percent of the total amount invested, that would be b/(a+b) = 1162.76/2362.76 = .4921...

Calculus
I get it!

Math
just use your usual distance formula. The final displacement is just 100*?(4^2+163^2) = 100?26585 = 16305m

Math
total distance is just the sum of all the separate pieces. I'm sure you can add them up. For the final location, just add up the separate displacements (in 100's of meters). (0,0) to (-23,0) to (-23,-175) to (-4,-175) to (-4,-163) Now you can figure the east-west, ...

Math
7*93 = ?

Chemistry
the net charge on any atom is zero. Only ions carry a net charge. one mole is 6.02 * 10^23 atoms. Each molecule of water (H2O) has two hydrogen atoms. each mole of H2O has a mass of 2*1 + 16 = 18 grams.

maths
2*2 = 4 cm^2 represents 5*5 = 25 km^2 so, you have 9/4 * 25 = 56.25 km^2

physics
v = vo + at s = vo*t + 1/2 at^2 vo + a*4.5 = 35 vo*4.5 + 1/2 a*4.5^2 = 100 so, (35-4.5a)(4.5) + 1/2 a * 4.5^2 = 100 a = 5.68 m/s^2

physics
I guess you want the total distance. Since v = at and s = vt + 1/2 at^2, s = (1/2)(1.4)(4.1)^2 + (4.1)(1.4)(1.8) + (1/2)(-1.8)(1.8)^2 = 19.18 m final velocity is v = 1.4*4.1 + (-1.8)*1.8 = 2.5 m/s average speed is 19.18m/(4.1+1.8)s = 3.25 m/s

algebra
t = 3m-8 g = m+5 m+t+g = 72 m + 3m-8 + m+5 = 72 5m-3 = 72 5m = 75 m = 15 Mark: 15 Tony: 37 Grant: 20 ------------ total: 72

computer science
I'd say C E might be considered, but the error in a double-precision value is out at the 14th significant figure, so I'd not consider that much of a loss of precision.

math
just solve both sides at once. -15<x-8<-4 add 8 everywhere: -15+8 < x-8+8 < -4+8 -7 < x < 4 what do you get for the others?

Algebra
Assuming the usual sloppiness with parentheses, I'll assume x=?(6x-27)+3 x-3 = ?(6x-27) x^2-6x+9 = 6x-27 x^2-12x+36 = 0 (x-6)^2 = 0 x = 6

Math
the whole lawn is 1/(3/5) = 5/3 as much as he can cut in 3/4 of an hour 5/3 * 3/4 = 5/4 or, keeping track of the units, (1 lawn) * (3/4 hr)/(3/5 lawn) = 3/4 * 5/3 = 5/4 hr

Math
however, if y*0.4 = 2 then y=5

Math
move the decimal point 5 places to the left: 0.0000356

computer science
Looks like B to me. Actually, it's good to 14 decimal significant figures, but 5.0 is good enough.

Math
If \$x was invested at 5%, then the rest \$(4100-x) was invested at 10% So, just add up the interest, and you have .05x + .10(4100-x) = 370 Now just find x ...

Algebra
Just use the distributive property: (x+3)(x^4-4x^2+5) = (x+3)(x^4) + (x+3)(-4x^2) + (x+3)(5) = x^5 + 3x^4 - 4x^3 - 12x^2 + 5x + 15

Algebra help pls
Nope. 7-(9x + 3) = 7-9x-3 = -9x+4

Algebra help pls
A: 3 = 4*1? Nope B: -4 = 4*(-1)? Yes C: -1 = 4(-4)? Nope D: -4 = 4*1? Nope

Algebra
#2 correct #3 correct

Engineering Mechanic
well, h(t) = 7.7t - 4.9t^2 max height is reached at t = -b/2a = 7.7/9.8 so plug that in to find h there.

Math
30=6*5=10*3, so 25/30, 9/30

Math
all correct.

Math
If b = -2, then since (-2)^2 = (-2)(-2) = +4 (-2)^3 = (-2)(-2)(-2) = -8 [-4b-8]+[-1-b^2]+2b^3 = [-4(-2)-8]+[-1-(-2)^2]+2(-2)^3 = [8-8]+[-1-4]+2(-8) = 0-5-16 = -21 9[9-8x] = 2x+3 81-72x = 2x+3 78 = 74x x = 78/74 = 39/37

Math
I agree

message for Dr. BOB
Dear Dr. Bob, I just wanted to thank you. You helped me graduate from college by helping me with with chemistry and now I am getting my master's degree. You have no idea what you have done for me. Again, THANK YOU!

English
thank you

English
With which of these statements does the crone in "The Wife of Bath’s Tale" save the life of the knight? • “A woman wants… sovereignty/Over her husband as over her lover…” • "It's little wonder if I twist and wallow!/God ...

English
thank you

English
What is the MOST likely reason that Chaucer presents The Canterbury Tales as a first-hand account? to establish that he actually did observe the events he describes to create a sense of immediacy and authenticity to prove that the characters in the work had actually told him ...

English
That's the site as well as reading the tale where I came up with the doctor.

English
from The Canterbury Tales: The Prologue With which of these Canterbury Tales characters does Chaucer illustrate a division between religious and scientific thought? the Narrator the Skipper the Doctor the Friar My answer is the doctor

English
Thank you

English
Which excerpt from “The Prologue” of The Canterbury Tales best indicates that the Nun is a compassionate person? (1 point) • “Her veil was gathered in a seemly way,/Her nose was elegant…” • “And well she sang a service, with a fine/...

Algebra
correct

Science
sorry. Neither one, if by "pure substance" you mean an element.

Math
m/6153 = 3/7

Math
so, what is the perimeter of the rectangle? The perimeter of a square is 4 times the side s. The area is s^2

Math
n+a < m+b

Math
those sure look like powers of 2 to me ...

math
n+3P6 = (n+3)(n+2)(n+1)(n)(n-1)(n-2) n+2P4 = (n+2)(n+1)(n)(n-1) (n+3)(n-2) = 14 n=4

Math
ummmm, 4^3, right?

Math
The mean is the total divided by how many there are. So, the new mean is (50*38-45-55)/48 = 37.5

Math
Remember the order of operations... 5^2x4+2^3 = 25x4+8 = 100+8 = 108

maths
If the fraction is n/d, we are told that d = 4n-1 Now we are told that (n+1)/(d+1) = 3/8 (n+1)/(4n-1+1) = 3/8 (n+1)/(4n) = 3/8 8(n+1) = 3(4n) 8n+8 = 12n 8 = 4n n = 2 The original fraction was 2/7 adding 1 top and bottom gives 3/8

Math
u = 1+?x ?x = u-1 du = 1/(2?x) dx = 1/(2u-2) dx so, dx = (2u-2) du ?1/(1+?x)^4 dx = ?1/u^4 (2u-2) du = 2?(1/u^3 - 1/u^4) du ...