Question

For the following system, if you isolated x in the second equation to use the Substitution Method, what expression would you substitute into the first equation?

2x + y = 8
-x - 3y = -12

3y + 12

-3y + 12

3y - 12

-3y - 12

Answer 1

Why don't you try isolating x in the second equation?

Answer 2

how would i do that?

Answer 3

Remember your algebra. You need to undo things that get done to x by doing the opposite to both sides. I'll give you an example, okay?
2x+6y = 10
6y gets added to x, so I need to undo that by doing the opposite. What is the opposite of adding 6y? Subtracting 6y. So I do that to both sides and get:
2x +6y -6y = 10-6y
2x = 10-6y
Now, I look and see that x is multiplied by 2. To undo that, I can divide by 2, but I need to do that to both sides so I get:
(2x)/2 = (10/2) - (6y/2)
x = 5-3y