Answer:
x = -12.
Explanation:
Number in the square next to 5 = 3+x.
Number to the right of this one = x + 1
From left to right the umbers in the second row = 5 + 3 + x
and 3 + x + x + 1
= x + 8 and 2x + 4.
So x + 8 + 2x + 4 = 2x
so 3x + 12 = 2x
x + 12 = 0
x = -12.