Step 1) Solve the first equation for xx:
x + y = 4x+y=4
x + y - color(red)(y) = 4 - color(red)(y)x+y−y=4−y
x + 0 = 4 - yx+0=4−y
x = 4 - yx=4−y
Step 2) Substitute (4 - y)(4−y) for xx in the second equation and solve for yy:
-3x + y = -8−3x+y=−8 becomes:
-3(4 - y) + y = -8−3(4−y)+y=−8
(-3 xx 4) + (3 xx y) + y = -8(−3×4)+(3×y)+y=−8
-12 + 3y + y = -8−12+3y+y=−8
-12 + color(red)(12) + 3y + y = -8 + color(red)(12)−12+12+3y+y=−8+12
0 + 3y + y = 40+3y+y=4
3y + y = 43y+y=4
3y + 1y = 43y+1y=4
(3 + 1)y = 4(3+1)y=4
4y = 44y=4
(4y)/color(red)(4) = 4/color(red)(4)4y4=44
y = 1y=1
Step 3) Substitute 11 for yy in the solution to the first equation at the end of Step 1 and calculate xx:
x = 4 - yx=4−y becomes:
x = 4 - 1x=4−1
x = 3x=3
The Solution Is:
x = 3x=3 and y = 1y=1
Or
(3, 1)(3,1)
