How do you solve y=x-4y=x−4 and y=2xy=2x using substitution? Algebra Systems of Equations and Inequalities Systems Using Substitution 1 Answer Ch Mar 21, 2016 x=-4x=−4 y=-8y=−8 Explanation: y=x-4y=x−4 y=2xy=2x We know that yy is 2x2x so we replace yy in the first equation with 2x2x. 2x=x-42x=x−4 2x-x=-42x−x=−4 x=-4x=−4 If yy is 2x2x, then yy=(-4)x2= -8. x=-4x=−4 y=-8y=−8 Answer link Related questions How do you solve systems of equations using the substitution method? How do you check your solutions to a systems of equations using the substitution method? When is the substitution method easier to use? How do you know if a solution is "no solution" or "infinite" when using the substitution method? How do you solve y=-6x-3y=−6x−3 and y=3y=3 using the substitution method? How do you solve 12y-3x=-112y−3x=−1 and x-4y=1x−4y=1 using the substitution method? Which method do you use to solve the system of equations y=1/4x-14y=14x−14 and y=19/8x+7y=198x+7? What are the 2 numbers if the sum is 70 and they differ by 11? How do you solve x+y=5x+y=5 and 3x+y=153x+y=15 using the substitution method? What is the point of intersection of the lines x+2y=4x+2y=4 and -x-3y=-7−x−3y=−7? See all questions in Systems Using Substitution Impact of this question 1556 views around the world You can reuse this answer Creative Commons License