Question

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

y = 96

y = 144

y = 256

y = 384

Answer 1

If y varies directly we can follow the format of direct variation as \[\large y=kx^2\]\[\large x=3 \ ,\ \ y=54\]first we solve for k.\[\large 54=(3)^2k\]\[\large 54 = 9k\]\[\large k=6\] Now we're asked to find y when \(x=8\)
\[\large y=(8)(6)\]\[\large y =?\]

Answer 2

12

Answer 3

48

Answer 4

srry

Answer 5

Sorry I, too, made a mistake.

Answer 6

288

Answer 7

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

y = 96

y = 144

y = 256

y = 384

Answer 8

One more time! lol.
\[\large y=kx^2\]\[\large k= 6 \ ,\ x=8\]\[\large y=(6)(8)^2\]\[\large y= 6 \times 64\]\[\large y=384\] I had mixed up my k and my x. :(