SOLUTION: x varies inversely as y^2, and x = 4 when y = 10. Find x when y = 2. a. x = 5 b. x = 80 c. x = 100

Algebra ->  Proportions  -> Lessons -> SOLUTION: x varies inversely as y^2, and x = 4 when y = 10. Find x when y = 2. a. x = 5 b. x = 80 c. x = 100       Log On


   

Question 1065683: x varies inversely as y^2, and x = 4 when y = 10. Find x when y = 2.

a. x = 5
b. x = 80
c. x = 100
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
x varies inversely as y^2,
matrix%281%2C3%2Cx%2C%22%22=%22%22%2Ck%2Fy%5E2%29
and x = 4 when y = 10.
 matrix%281%2C3%2C4%2C%22%22=%22%22%2Ck%2F10%5E2%29

matrix%281%2C3%2C4%2C%22%22=%22%22%2Ck%2F100%29

matrix%281%2C3%2C400%2C%22%22=%22%22%2Ck%29

Substitute 400 for k in

matrix%281%2C3%2Cx%2C%22%22=%22%22%2Ck%2Fy%5E2%29

matrix%281%2C3%2Cx%2C%22%22=%22%22%2C400%2Fy%5E2%29

That's the equation for x in terms of y.
Find x when y = 2.
Substitute 2 for y

matrix%281%2C3%2Cx%2C%22%22=%22%22%2C400%2F2%5E2%29

matrix%281%2C3%2Cx%2C%22%22=%22%22%2C400%2F4%29

matrix%281%2C3%2Cx%2C%22%22=%22%22%2C100%29

Edwin