How do you solve the following system?: # 4x-5y=5 , 2x + y = -8 #

1 Answer
Nov 15, 2015

You would have to solve using Substitution.


First, set up your equation like this:


You will need to start by solving for one variable. Take the bottom equation and isolate y. You should get; y=-8-2x. From there, plug that value into the top equation for y. The top equation should now say: 4x-5(-8-2x)=5. Now you have only one variable in an equation, and you can solve for x. You should get 14x=-35, or x = 2.5 Now that you have your x value, you can plug it into either equation to find y. Let's say you used the bottom one. You would have 2(2.5)+y=-8, or 5+y=-8, or y=-13.
If you want to check to make sure the equation is correct, you can plug the y and/or x values back into the original equations and it should work out!