Problema Solution
If Y is directly proportional to x^2 and if the difference in the values of Y when x =1 and x=3 is 32, find the value of Y when x =-2.
Answer provided by our tutors
If y is directly proportional to x^2 it can be written as y(x) = k*(x^2) where k is a constant. Then
|y(1) - y(3)| = 32
| k - 9k| = 32
8*|k| = 32
|k| = 32/8
|k| = 4
when k = -4 then y = -4x^2 and y(-2) = (-4)*(-2) = 8
when k = 4 then y = 4*x^2 and y(-2) = 4*(-2) = -8
If y is directly proportional to x^2 it can be written as y(x) = k*(x^2) where k is a constant. Then
|y(1) - y(3)| = 32
| k - 9k| = 32
8*|k| = 32
|k| = 32/8
|k| = 4
when k = -4 then y = -4x^2 and y(-2) = (-4)*(-2)^2 = - 16
when k = 4 then y = 4*x^2 and y(-2) = 4*(-2)^2 = 16