Step 1) Solve the first equation for xx:
-4x + 4y = 4−4x+4y=4
-4x + 4y - color(red)(4y) = 4 - color(red)(4y)−4x+4y−4y=4−4y
-4x + 0 = 4 - 4y−4x+0=4−4y
-4x = 4 - 4y−4x=4−4y
(-4x)/color(red)(-4) = (4 - 4y)/color(red)(-4)−4x−4=4−4y−4
x = 4/color(red)(-4) - (4y)/color(red)(-4)x=4−4−4y−4
x = -1 + yx=−1+y
Step 2) Substitute (-1 + y)(−1+y) for xx in the second equation and solve for yy:
y = 9x + 73y=9x+73 becomes:
y = 9(-1 + y) + 73y=9(−1+y)+73
y = (9 * -1) + (9 * y) + 73y=(9⋅−1)+(9⋅y)+73
y = -9 + 9y + 73y=−9+9y+73
y - color(red)(9y) = -9 + 9y - color(red)(9y) + 73y−9y=−9+9y−9y+73
1y - color(red)(9y) = -9 + 0 + 731y−9y=−9+0+73
(1 - color(red)(9))y = -9 + 73(1−9)y=−9+73
-8y = 64−8y=64
(-8y)/color(red)(-8) = 64/color(red)(-8)−8y−8=64−8
y = -8y=−8
Step 3) Substitute -8−8 for yy in the solution to the first equation at the end of Step 1 and calculate xx:
x = -1 + yx=−1+y becomes:
x = -1 + (-8)x=−1+(−8)
x = -1 - 8x=−1−8
x = -9x=−9
The Solution Is:
x = -9x=−9 and y = -8y=−8
Or
(-9, -8)(−9,−8)
