Step 1) Solve the first equation for y:
3x + y = -1
3x - color(red)(3x) + y = -1 - color(red)(3x)
0 + y = -1 - 3x
y = -1 - 3x
Step 2) Substitute (-1 - 3x) for y in the second equation and solve for x:
2x - y = -4 becomes:
2x - (-1 - 3x) = -4
2x + 1 + 3x = -4
2x + 3x + 1 = -4
(2 + 3)x + 1 = -4
5x + 1 = -4
5x + 1 - color(red)(1) = -4 - color(red)(1)
5x + 0 = -5
5x = -5
(5x)/color(red)(5) = -5/color(red)(5)
(color(red)(cancel(color(black)(5)))x)/cancel(color(red)(5)) = -1
x = -1
Step 3) Substitute -1 for x in the solution to the first equation at the end of Step 1 and calculate y:
y = -1 - 3x becomes:
y = -1 - (3 xx -1)
y = -1 - (-3)
y = -1 + 3
y = 2
The Solution Is:
x = -1 and y = 2
Or
(-1, 2)
