Question

Select the correct answer.
What is the difference of the values of the two variables in this system of equations?

y = 2x + 1
x + 3y = 10
A.
0
B.
1
C.
2
D.
3

Answer 1

Substitute y = 2x + 1 into x + 3y = 10:

x + 3(2x + 1) = 10
x + 6x + 3 = 10
7x = 7 → x = 1

y = 2(1) + 1 = 3

Difference y − x = 3 − 1 = 2.

Answer: C.