Question

What is the solution to the following system?
-2x-y=1
-4x-2y=-1

Answer 1

set one equation equal to y, then substitute it into the other equation

-2x-y=1
-4x-2y=-1

-4x-2y=-1
-2y = -1+4x
y = (-1+4x)/-2
y = (-1/-2)+(4x/-2)
y = (1/2) + -2x

now plug this into the other untouched equation
-2x-y=1
-2x-((1/2) + -2x)=1
now solve for x!

once you get x, you can solve for y by plugging in x into either of the original equations.