Question

Y is directly proportional to (x+2)2 when x=8 y=250 find y when x=4

Answer 1

Y=150

Explanation:

Just apply the proportionality rulw and solve for k. Then substitute the value of k into the equation.

Answer 2

90

Explanation:

Let the constant of proportionality be K

So that;

Y= K(x+2)^2

This means

For two corresponding points (x1,y1) and (x2,y2) we have;

Y1/(x1+2)^2= Y2/(x2+2)^2

If we consider x=8 y=250 as point (x1,y1) and y when x=4 as (x2,y2) we have ;

250/(8+2)^2 =y/(4+2)^2

250/(10)^2 = y/(6)^2

250/100 = y/36

250/100 × 36 = y

90= y

y=90