Question

How you solve this by using solving proportions

Answer 1

3/(x + 4) = (x + 2)/5

Multiply both sides by 5 :

5 × 3/(x + 4) = 5 × (x + 2)/5

15/(x + 4) = x + 2

Multiply both sides by x + 4 :

(x + 4) × 15/(x + 4) = (x + 4) × (x + 2)

Provided that x + 4 ≠ 0, we can cancel the factors of x + 4 on the left side:

15 = (x + 4) (x + 2)

Expand the product on the right side:

15 = x² + 6x + 8

Move everything to one side:

0 = x² + 6x - 7

We can factorize easily in this case
0 = (x + 7) (x - 1)

Then

x + 7 = 0   or   x - 1 = 0

⇒   x = -7   or   x = 1