Question

Which of the following would NOT be the result of a substitution in the following system?

2x + y = 7
y - x = 1
Answers
A. 2(y + 1) + y = 7
B. 2x + x + 1 = 7
C. 7 - 2x - x = 1

Answer 1

A

Explanation:

y-x=1 so to solve for x

-x = -y + 1

x = (y - 1) so A is incorrect because it substitutes (y +1) for x