Question

Zina solves a system of linear equations by elimination and finds a solution of (2, 2). One of the equations is a + b = 4. What is the other equation?

Answer 1

A - b = 0 <=== ur other equation

check...
a + b = 4
a - b = 0
--------------add
2a = 4
a = 4/2
a = 2

a - b = 0
2 - b = 0
-b = 0 - 2
-b = -2
b = 2

solution is (2,2)