Question

Solve by substitution or elimination; x+2y=-1 x-y=5

Answer 1

I would love to use substitution (It is simplier that way I guess)

solve your system of equations.

x+2y=−1;x−y=5

Solve x+2y=−1 for x:

x+2y+−2y=−1+−2y(Add -2y to both sides)

x=−2y−1

Substitute (−2y−1) for x in x−y=5:

x−y=5

−2y−1−y=5

−3y−1=5(Simplify both sides of the equation)

−3y−1+1=5+1(Add 1 to both sides)

−3y=6

−3y/−3 = 6/−3(Divide both sides by -3)

y=−2

Substitute (−2) for y in x=−2y−1:

x=−2y−1

x=(−2)(−2)−1

x=3(Simplify both sides of the equation)

So the answer is (x = 3 and y = -2)

Answer 2

I used substitution

x-y=5

x-y=5
+y +y
x= y+5

x+2y=-1

y+5+2y=-1
3y+5=-1
-5 -5
3y=-6
÷3 ÷3
y=-2

x-(-2)=5
x+2=5
-2 -2
x=3

x=3 y=-2