Y is directly proportional to x 2 . If y = 8 when x = 2 find y when x = 5

y=20 when x=5

Step-by-step explanation:

you can find the value of y when x is 1

(it'll be 4)

then you can multiply 4 by 5 which is 20

y = 50

Step-by-step explanation:

Given y is directly proportional to x² then the equation relating them is

y = kx² ← k is the constant of proportion

To find k use the condition y = 8 when x = 2 , then

8 = k × 2² = 4k ( divide both sides by 4 (

2 = k

y = 2x² ← equation of proportion

When x = 5 , then

y = 2 × 5² = 2 × 25 = 50