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Numeric_Fractions/388123: what is the answer to 5t+t+13 over 7t=, the last part is a fraction 13 over 7 with the t after the fraction =
1 solutions

Answer 274454 by Alan3354(31487) About Me  on 2010-12-20 21:19:46 (Show Source):
You can put this solution on YOUR website!
It's ambiguous. Use parentheses.


Evaluation_Word_Problems/388107: subtract a number from 10
1 solutions

Answer 274436 by Alan3354(31487) About Me  on 2010-12-20 17:52:28 (Show Source):
You can put this solution on YOUR website!
If n is "the number"
= 10 - n


Expressions-with-variables/388082: please help me with this problem in doing elimantion 3x-10y-29=0
-11x-10y+13=0
1 solutions

Answer 274397 by Alan3354(31487) About Me  on 2010-12-20 15:10:15 (Show Source):
You can put this solution on YOUR website!
The y terms have the same coefficient, so subtract.


Surface-area/388011: Two solid spheres have surface areas 144 pi sq.cm and 256 pi sq.cm, respectively. They are melted and recast to form a larger sphere. Find the surface area of this sphere in sq.cm.
1 solutions

Answer 274396 by Alan3354(31487) About Me  on 2010-12-20 15:00:07 (Show Source):
You can put this solution on YOUR website!
Two solid spheres have surface areas 144 pi sq.cm and 256 pi sq.cm, respectively. They are melted and recast to form a larger sphere. Find the surface area of this sphere in sq.cm.
---------------------
Find the radii, then the volumes.
Add the volumes, find the radius of the total.
Find the surface area of the total.
--------------
Area+=+4%2Api%2Ar%5E2
for 144pi sq cm, r = 6
for 256pi sq cm, r = 8
----------------
Vol+=+4%2Api%2Ar%5E3%2F3
for r = 6, V = 288pi cc
for r = 8, V = 2048pi/3 cc
Total volume = 2912pi/3 cc
r =~ 8.996 cm
SA total =~ 1016.945 sq cm
----------------
=~ 323.7pi sq cm, less the the sum of the 2 original areas


Travel_Word_Problems/388062: the angles of elevation to an airplane from two points A and B on level ground are 51(degrees) and 68(degrees), respectively. The points A and B are 2.5 miles apart, and the airplane is east of both points in the same vertical plane. Find the altitude of plane.
1 solutions

Answer 274395 by Alan3354(31487) About Me  on 2010-12-20 14:49:31 (Show Source):
You can put this solution on YOUR website!
I just did this one.


Travel_Word_Problems/388066: the angles of elevation to an airplane from two points A and B on level ground are 51 degrees and 68 degrees respectively. The points A and B are 2.5 miles apart, and the airplane is east of both points in the same vertical plane. Find the altitude of the plane.
thanks for the help! i've been stuck on this problem for like an hour now!
1 solutions

Answer 274392 by Alan3354(31487) About Me  on 2010-12-20 14:41:29 (Show Source):
You can put this solution on YOUR website!
the angles of elevation to an airplane from two points A and B on level ground are 51 degrees and 68 degrees respectively. The points A and B are 2.5 miles apart, and the airplane is east of both points in the same vertical plane. Find the altitude of the plane.
--------------------------
The interior angle at point B is 180 - 68 = 112º
Angle C (at the plane) = 180 - (A+B) = 17º
-----------
Use the Law of Sines to find side AC
AB/sin(17) = AC/sin(112)
AC = AB*sin(112)/sin(17) =~ 7.928 miles
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Altitude = AC*sin(51) =~ 6.163 miles
= 32532 feet


Travel_Word_Problems/388070: A subway train travels 296 miels daily how far does the train travel in a week?
1 solutions

Answer 274388 by Alan3354(31487) About Me  on 2010-12-20 14:28:46 (Show Source):
You can put this solution on YOUR website!
If it's the same for weekends, it's
296 times 7.


Quadratic_Equations/388044: how many seconds will the ball be 75 ft haigh after hit 2 feet off the ground and initial upward velocity of 90 ft / sec.
75h = 2 ho + 90 t - 16 t squared
1 solutions

Answer 274383 by Alan3354(31487) About Me  on 2010-12-20 13:56:54 (Show Source):
You can put this solution on YOUR website!
how many seconds will the ball be 75 ft haigh after hit 2 feet off the ground and initial upward velocity of 90 ft / sec.
75h = 2 ho + 90 t - 16 t squared
-----------------
h(t) = -16t^2 + 90t + 2
At h = 75:
-16t^2 + 90t + 2 = 75
-16t^2 + 90t - 73 = 0
Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case -16x%5E2%2B90x%2B-73+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%2890%29%5E2-4%2A-16%2A-73=3428.

Discriminant d=3428 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-90%2B-sqrt%28+3428+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%2890%29%2Bsqrt%28+3428+%29%29%2F2%5C-16+=+0.982839853961944
x%5B2%5D+=+%28-%2890%29-sqrt%28+3428+%29%29%2F2%5C-16+=+4.64216014603806

Quadratic expression -16x%5E2%2B90x%2B-73 can be factored:
-16x%5E2%2B90x%2B-73+=+%28x-0.982839853961944%29%2A%28x-4.64216014603806%29
Again, the answer is: 0.982839853961944, 4.64216014603806. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+-16%2Ax%5E2%2B90%2Ax%2B-73+%29

----------------------
The ball passes 75 feet twice, ascending at t = 0.982839853961944, and descending at t = 4.64216014603806 seconds.
-------------------
The ball is exactly 75 feet high for zero time, or dt seconds.
It is at or above 75 feet for the difference between the 2 times above,
=~ 3.659 seconds




Linear_Equations_And_Systems_Word_Problems/388054: The ratio of boys to girls in a class is 4:7. There are 88 students in the class. How many boys are there?
Thanks for your help.
1 solutions

Answer 274370 by Alan3354(31487) About Me  on 2010-12-20 13:28:46 (Show Source):
You can put this solution on YOUR website!
The ratio of boys to girls in a class is 4:7. There are 88 students in the class. How many boys are there?
------------
Add the numbers in the ratio.
4 + 7 = 11
88/11 = 8
--> 8*4 = 32 boys
--> 8*7 = 56 girls


Rate-of-work-word-problems/387936: An aquarium tank can hold 6000 liters of water. There are two pipes that can be used to fill the tank. The first pipe alone can fill the tank in 50 minutes. The second pipe can fill the tank in 75 minutes by itself. When both pipes are working together, how long does it take them to fill the tank?
1 solutions

Answer 274243 by Alan3354(31487) About Me  on 2010-12-19 21:12:07 (Show Source):
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The 1st pipe fills 1/50 of the tank per minute.
The 2nd pipe fills 1/75 of the tank per minute.
Can you finish it?


Travel_Word_Problems/387938: A ball is thrown upward with an initial speed of 24.5 m/s. When is it 19.6m high?

1 solutions

Answer 274242 by Alan3354(31487) About Me  on 2010-12-19 21:10:34 (Show Source):
You can put this solution on YOUR website!
You didn't specify the equation of motion, or the starting height.
---------
h(t) = -4.9t^2 + vt is commonly used, assuming h(0) = 0
h(t) = -4.9t^2 + 24.5t
-4.9t^2 + 24.5t = 19.6
t^2 - 5t + 4 = 0
(t-1)*(t-4) = 0
t = 1 second going up
t = 4 seconds descending


Square-cubic-other-roots/387935: Multiply: %28sqrt10+%2B+5sqrt5%29%28sqrt10+-+5sqrt5%29
Type an exact answer, using radicals as needed.
1 solutions

Answer 274240 by Alan3354(31487) About Me  on 2010-12-19 21:06:21 (Show Source):
You can put this solution on YOUR website!
This is (a + b)*(a - b)
= a^2 - b^2
------------
%28sqrt10+%2B+5sqrt5%29%28sqrt10+-+5sqrt5%29
= 10 - 125
= -115



Equations/387922: x-3y=-8
y+2=1
x+42=7
How do I solve this problem?
1 solutions

Answer 274225 by Alan3354(31487) About Me  on 2010-12-19 19:44:02 (Show Source):
You can put this solution on YOUR website!
x-3y=-8
y+2=1
x+42=7
How do I solve this problem?
------------
y+2=1
y = -1
---------
x+42=7
x = -35
-------
The 1st eqn doesn't fit.


Coordinate-system/387909: x+y=1
1 solutions

Answer 274224 by Alan3354(31487) About Me  on 2010-12-19 19:38:41 (Show Source):
You can put this solution on YOUR website!
Do you have a question?


Numeric_Fractions/387885: solve these three problems.
y= -3/2(-2)+1
y= -3/2(4)+1
y= -3/2(6)+1
1 solutions

Answer 274201 by Alan3354(31487) About Me  on 2010-12-19 17:12:52 (Show Source):
You can put this solution on YOUR website!
solve these three problems.
y= -3/2(-2)+1 = 3 + 1 = 4
---------------
y= -3/2(4)+1
Multiply 4 by -3/2 and add 1.
----------------
y= -3/2(6)+1


Miscellaneous_Word_Problems/387884: Preform the indicated operation. Wright the answer in scientific notation.
( 6 x 10^-2)(5.67 x 10^3)

This is how I put this into the calculator and I got 385.344. I move the decimal over two places to get the answer 3.85 x 10^2. What happened to the .344?
I am studying for a test and I have the answers for the pre-test and I am allowed to use the calculator on the test. I t will help so much if I really knew how to use it.
1 solutions

Answer 274200 by Alan3354(31487) About Me  on 2010-12-19 17:11:17 (Show Source):
You can put this solution on YOUR website!
( 6 x 10^-2)(5.67 x 10^3)
= 6*5.67*10^1
= 34.02*10
= 3.402*10^2
-------------
How did you get 385.344 ?


Miscellaneous_Word_Problems/387874: John wants to fence a 150 square meters rectangular field. He wants the legnth and width to be natural numbers. What field dimension will require the least amount of fencing?
1 solutions

Answer 274199 by Alan3354(31487) About Me  on 2010-12-19 17:07:53 (Show Source):
You can put this solution on YOUR website!
The length and width would be the factors of 150.
150 =
1 x 150
2 x 75
3 x 50
5 x 30
10 x 15
--------
10 by 15 is the smallest perimeter.


logarithm/387889: 9 1/2=3 convert to a logarithmic equation

1 solutions

Answer 274198 by Alan3354(31487) About Me  on 2010-12-19 17:04:53 (Show Source):
You can put this solution on YOUR website!
9.5 does not equal 3.


Radicals/387827: How do I solve:
(5 sqrt10 + 7 sqrt5)(2 sqrt5 + sqrt10)
sorry but there is no square root button on the keyboard. I hope you can understand where the square roots are. Thank You.
1 solutions

Answer 274197 by Alan3354(31487) About Me  on 2010-12-19 17:04:13 (Show Source):
You can put this solution on YOUR website!
There's nothing to solve, it's not an equation.
Multiply it, the same as any other binomials.


Expressions-with-variables/387861: Can you help me with this question? If a bride and groom want to serve a nut mixture containing 25% nut peanuts, and the bride has available mixtures that are either 40% or 10% peanuts, how much of each type should be mixed to get 10lb that are 25% peanuts? Thank you! Shelly
1 solutions

Answer 274196 by Alan3354(31487) About Me  on 2010-12-19 17:00:59 (Show Source):
You can put this solution on YOUR website!
Since 25% is the midpoint of 10 and 40, it's equal amounts.


Linear-systems/387887: solve the system x-y-5z+-13
4x+2y+2z=6
3x-2y+2z=24
1 solutions

Answer 274195 by Alan3354(31487) About Me  on 2010-12-19 16:59:17 (Show Source):
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The 1st line has no equal sign.


Exponents/387800: Simplify and express your answer using positive exponents only.
(x2/5)3/2
1 solutions

Answer 274194 by Alan3354(31487) About Me  on 2010-12-19 16:58:36 (Show Source):
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I don't see any exponents.


Linear-systems/387815: solve the lnear equatin by using elimnation
x+5y=28
-x-2y=-13
1 solutions

Answer 274150 by Alan3354(31487) About Me  on 2010-12-19 12:57:10 (Show Source):
You can put this solution on YOUR website!
Add the 2 equations.


Square-cubic-other-roots/387744: Add. Simplify if possible
(3r)/(r^(2)-25) + (r)/(r-5)
for this I ended up with
r(r+8)/(r-5)(r+5)
is this right???
1 solutions

Answer 274132 by Alan3354(31487) About Me  on 2010-12-19 09:30:37 (Show Source):
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Add. Simplify if possible
3r%2F%28r%5E2-25%29+%2B+r%2F%28r-5%29
= (((3r/(r^2-25) + r(r+5)/(r^2-25)}}}
= %28r%5E2%2B8r%29%2F%28r%5E2-25%29
= r(r+8)/(r-5)(r+5) Same thing.
------------------
for this I ended up with
r(r+8)/(r-5)(r+5)
is this right???


Square-cubic-other-roots/387743: Multiply
(4√(5)-12√(7))*(5√(5)+15√(7))
I honestly don't even know where to start!!
1 solutions

Answer 274131 by Alan3354(31487) About Me  on 2010-12-19 09:21:47 (Show Source):
You can put this solution on YOUR website!
%284sqrt%285%29+-+12sqrt%287%29+%29%2A%285sqrt%285%29+%2B+15sqrt%287%29+%29
Multiply the terms the same as in any multiplication of binomials. FOIL, etc.
= 4%2A5%2Asqrt%2825%29+%2B+4%2A15%2Asqrt%2835%29+-+60sqrt%2835%29+-180sqrt%2849%29
= 20%2A5+%2B+60sqrt%2835%29+-+60+sqrt%2835%29+-+180%2A7
= 100 - 1260
= -1160


Polynomials-and-rational-expressions/387751: Please help solve problem
x^3 - 7x + 2
1 solutions

Answer 274130 by Alan3354(31487) About Me  on 2010-12-19 09:14:30 (Show Source):
You can put this solution on YOUR website!
It's not an equation, there's nothing to solve.


Systems-of-equations/387752: I want to know how to calculate 32 to the power of 1/5
1 solutions

Answer 274129 by Alan3354(31487) About Me  on 2010-12-19 09:12:05 (Show Source):
You can put this solution on YOUR website!
You can use a calculator.
If you know that 2^5 = 32, you can figure it out.
You can use logarithms.


Numbers_Word_Problems/387753: the sum of three consective positive integer is 315.find the number
1 solutions

Answer 274128 by Alan3354(31487) About Me  on 2010-12-19 09:10:47 (Show Source):
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315/3 = 105, the middle number


Travel_Word_Problems/387691: A motorboat travels 441mi in 7 hours going upstream and 522mi in 6 hours going downstream. What is the rate of the boat in still water and what is the rate of the current?
1 solutions

Answer 274075 by Alan3354(31487) About Me  on 2010-12-18 21:54:45 (Show Source):
You can put this solution on YOUR website!
A motorboat travels 441mi in 7 hours going upstream and 522mi in 6 hours going downstream. What is the rate of the boat in still water and what is the rate of the current?
-------------------
441/7 = 63 mph
522/6 = 87 mph
The boat's speed is the average (63 + 87)/2 = 75 mph
The current is the difference 87 - 72 = 12 mph


logarithm/387701: Please help solve 5(x-12)^1/3 + 6 =51
1 solutions

Answer 274074 by Alan3354(31487) About Me  on 2010-12-18 21:52:16 (Show Source):
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5(x-12)^1/3 + 6 =51
What did you try?
5(x-12)^1/3 + 6 =51
5(x-12)^1/3 = 45
(x-12)^1/3 = 9
Can you finish it?


Linear-equations/387706: Given the quadratic function f(x) = x2 – 12x + 36, find a value of x such that f(x) = 9.


1 solutions

Answer 274073 by Alan3354(31487) About Me  on 2010-12-18 21:49:27 (Show Source):
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Given the quadratic function f(x) = x2 – 12x + 36, find a value of x such that f(x) = 9.
-----------
f(x) = x^2 – 12x + 36 = 9
x%5E2+-+12x+%2B+27+=+0
(x-9)(x-3) = 0
x = 3, x = 9