(04.03 MC) Explain how System 1 becomes equivalent to System 2.

System 1:
Ax + By = C
Lx + My = N

System 2:
Ax + By = C
(A − L)x + (B − M)y = C − N

Square a has a side length of (2x-7) and square b has a side length of (-4x+18). how much bigger is the perimeter of square b than square a?and show all work! you so