Question

What value of x makes f(x) = -2 if f(x) = 3.4x - 7.1

A. -13.9 B. -1.5

C. 1.5 D. 2.8

Answer 1

Option C

For x = 1.5 we get f(x) = -2

Solution:

Given function is:

`f(x) = 3.4x - 7.1`

We have to find the value of "x" so that f(x) = -2

Substitute f(x) = -2 in given function

`-2 = 3.4x - 7.1`

Solve for "x" by moving the constants to one side and variables to other side

`3.4x = -2 + 7.1\\\\3.4x = 5.1\\\\ \text{Divide both the sides of equation by 3.4 }\\\\x = (5.1)/(3.4)\\\\x = 1.5`

For x = 1.5 we get f(x) = -2

We can verify by substituting x = 1.5 in given function

`f(1.5) = 3.4(1.5) - 7.1\\\\f(1.5) =5.1-7.1\\\\f(1.5) = -2`

Thus for x = 1.5 we get f(x) = -2