Answer:
Input: -7
Explanation:
We need to make an equation before solving for x, the input.
Output of A: x × 5 - 4 = 5x - 4
Output of B: x × 3 + 8 = 3x + 8
You know that the output of A is three times the output of B:
5x - 4 = 3(3x + 8)
Now that we have an equation, we can work out the value of x.
5x - 4 = 9x + 24
Isolate like terms.
-24 - 4 = 9x - 5x
Evaluate.
4x = -28
Find x.
x = -28 ÷ 4
x = -7