Question

If g(x) = 2(x − 4), find the value of x if g(x) = 20.

Answer 1

Here you're given a numerical value for g(x) and an algebraic formula for g(x) also. Equate the two: g(x) = 2(x - 4) = g(x) = 20.

Solve this for x:

Divide both sides by 2. We get: x - 4 = 10.

Add 4 to both sides, to isolate x: x = 14.

The value of x is 14.

Answer 2

`g(x)=2(x-4)\\\\g(x)=20\to2(x-4)=20\qquad\text{divide both sides by 2}\\\\x-4=10\qquad\text{add 4 to both sides}\\\\\boxed{x=14}`