Question

Zina solves a system of linear equations by elimination and finds that the solution to a system is (2, 2). One of the equations is a + b = 4. Which answer could be the other equation?

a + 3b = 4
2a + 2b = 2
4a + 4b = 8
a + 3b = 8

Answer 1

D. a + 3b = 8

Answer 2

Answer: a + 3b = 8

Explanation:

a + b = 4 is true, since (2,2) works: 2 + 2 = 4

Try (2,2) in the options to find which one is true for (2,2):

A) 2 + 3*2 = 4? No.

B) 4 + 4 = 2? No.

C) 8 + 8 = 8? No.

D) 2 + 6 = 8? YES.

Therefore, a + 3b = 8 can be another valid equation.