Question

Solve the system

y = 2 - x and y = 4x+7
A. (1,1)
B.(1,3)
C.(-1,3)
D.(-1,1)
E. no solution

Answer 1

Use substitution.

y = 2 - x and y = 4x + 7 can become

2 - x = 4x + 7

Now solve for x

-5 = 5x

-1 = x

Now plug -1 for x in either equation.

y = 2 - x -> y = 2 - (-1) -> y = 3
y = 4x + 7 -> y = 4*-1 + 7 -> y = -4 + 7 -> y = 3

So C) is the correct answer.