Answer:
x = -1 and y = 6
Step-by-step explanation:
y = x + 7
5x + 2y = 7
y - x = 7.............(1)
2y + 5x = 7......(2)
multiply equation (1) by 2
2y - 2x = 14
2y + 5x = 7
subtract equation (2) from (1)
2y - 2x = 14
- 2y + 5x = 7
-------------------
0 -7x = 7
-7x = 7
divide both sides by 7
-7x = 7
----- ----
7 7
-x = 1 multiply through by minus sign
x = -1
substitute x = -1 into equation (1)
y - x = 7
y - (-1) = 7
y + 1 = 7
y = 7 - 1
y = 6
