Answer:
x=10
y=0
Explanation:
In order to use substitution you need to pick an equation and get one of the variables alone. I'm going to use the second equation and get x alone.
x+2y=10 Subtract the 2y on both sides to get x by itself.
-2y -2y
x= -2y+10 Now plug this in to the first equation for x.
2(-2y+10)+4y= -20 To start you distribute the 2 to both terms inside the parenthesis.
2(-2y)+2(10)+4y= -20 Simplify.
-4y+20+4y= -20 Next add your like terms together (-4y+4y)
When you do this you should get 0y which just means y=0. Now you can take that and plug it into one of the equations for y. I choose to use the second equation again. x+2(0)=10, therefore x=10