Question

Given the linear function f(x) = −4x + 8, what is the value of x if f(x) = 24?

x = 104
x = −4
x = −8
x = −88

Answer 1

The value of x = -4

Explanation:

The given linear function is f(x) = -4x+8

We have to find the x corresponding to f(x) = 24

For our convenience, let f(x) = y

Then y = -4x + 8

This equation implies y in terms of x.

Isolating x to one side of the equation, we get,

x = (y - 8)/-4 = (8-y)/4

This equation gives x in terms of y.

So when f(x) = y = 24,

x = (8-24)/4

⇒ x = -4