Question

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

Answers:
A: 1,1
B: 1,3
C: -1,3
D: -1,1
E: no solution

Answer 1

y = 2 - x
so sub in 2 - x in place of y in the other equation

y = 4x + 7
2 - x = 4x + 7 --- add x to both sides
2 = 4x + x + 7
2 = 5x + 7 --- subtract 7 from both sides
2 - 7 = 5x
-5 = 5x --- divide both sides by 5
-5/5 = x
-1 = x

now sub -1 in for x in either equation to find y
y = 2 - x
y = 2 - (-1)
y = 2 + 1
y = 3

check..
y = 4x + 7
3 = 4(-1) + 7
3 = -4 + 7
3 = 3 (correct)

so your solution is : (-1,3)