Question

Which of the following is not a solution to the system of linear equations below?

x-2y=4
-2x+4y=-8
A. (2, –1) B. (4, 0) C. (0, 2) D. (6, 1)

Answer 1

Plug in until you get a false answer.

A (2,-1)
(2)-2(-1)=4
2+2=4
-2(2)+4(-1)=-8
-4-4=-8

B(4,0)
(4)-2(0)=4
4-0=4
-2(4)+4(0)=-8
-8+0=-8

C(0,2)
(0)-2(2)=4
0-4=4
-4=4
-2(0)+4(2)=-8
0+8=-8
8=-8

D(6,1)
(6)-2(1)=4
6-2=4
-2(6)+4(1)=-8
-12+4=-8

The correct answer is C because (0,2) makes the equation untrue.