Question

3. Solve the system using substitution.

y=8-x
7=2-y
A. (5,13)
B. (13,-5)
C. (3,5)
D. (21,-13)

Answer 1

y=8-x
7=2-y

First substitute the y in the second problum for 8-x
7=2-8+x

Now subtract the 8 and the 2
7=-6+x

add the -6 on both sides to solve for x
13=x

Now substitute the x for the 13 into the first problum
y=8-13

Subtract the 13 and 8 to solve for y
y=-5

Your answer
y=-5
x=13
so your correct answer would be
B:(13,-5)