SOLUTION: Z varies directly as x^2. If z=50 when x=5, find when x=7

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Question 1199201: Z varies directly as x^2. If z=50 when x=5, find when x=7
Found 2 solutions by ikleyn, greenestamps:
Answer by ikleyn(52778) About Me  (Show Source):
You can put this solution on YOUR website!
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The problem says that  z = kx^2.


It also says that  50 = k*5^2 = 25k,  which implies  k = 2.


Hence,  z = 2x^2.


When x= 7,  z = 2*7^2 = 2*49 = 98.    ANSWER

Solved, with complete explanations.


Best wishes are also attached.



Answer by greenestamps(13198) About Me  (Show Source):
You can put this solution on YOUR website!


z varies directly as the square of x, so when x changes by a factor of 7/5, z changes by a factor of (7/5)^2.

ANSWER: %2850%29%28%287%2F5%29%5E2%29=50%2849%2F25%29=49%2A2=98