Question

y varies directly as the square of x. When x = 3, y = 54. Find y when x = 8 please help

Answer 1

"y varies directly as the square of x" translates to y = kx^2

Answer 2

When x = 3, y = 54, so plug these values in to get


y = kx^2

54 = k*3^2


Then solve for k

54 = k*9

54/9 = k

6 = k

k = 6

So we get the equation y = 6x^2

Answer 3

Your last step is to plug in x = 8 into y = 6x^2 and evaluate to find y.

Answer 4

thank you :) .. so what are these kind of problems callled

Answer 5

variation problems, in this case, it's a direct variation problem

Answer 6

you'll also come across inverse variation problems, but that's for another problem

Answer 7

thank you so much #i appreciate u helping me

Answer 8

you're welcome

Answer 9

thank you # algebra 2 is killing lolz

Answer 10

just keep at it and you'll get it eventually

Answer 11

thx:)