since the lengths of all those four sides are in a 3:2:6:7 ratio, and the whole perimeter is 126, what we do is, simply divide the whole by (3+2+6+7) and distribute accordingly.

by starting from the number on the z axis and going up from the y axis
Step-by-step explanation:
from,
f (x) = 2x-2+5
BUT x=-2
f (x) = 2 (-2)-2+5
= -4-2+5
= -6+5
= -1
so,
f (x) = -1