Substitution is where you substitute, basically. So, substitute "y" for y.
They have given you y: -3x+11.
They have also given you an equation for you to substitute y into: 3x+2y=7.
Now, you can create the substituted problem.
3x + 2(-3x + 11 ) = 7
Use distributive property.
3x + -6x + 22 = 7
Add like terms.
-3x + 22 = 7
Subtract 22 from 7.
-3x = -15
Divide.
x = 5.
Now, that you have x, plug "5" back into the original equations or at least one of them to find your y.
I will do both to show you.
3(5) + 2y = 7
15 + 2y = 7
2y = -8
y = -4
You would get -4 with the other equation, too.
y = -3(5) + 11
y = -15 + 11
y = -4
Now, since you have x= 5, y= -4, that would be equivalent to (5, -4) which would be answer choice D.
*side note* because only one of the answer choices started with x being equivalent to y, you wouldn't need to go through finding y as the only possible answer choice could be D. However, it is always good to check and make sure you didn't do anything wrong with x by finding y. Also, I have done y for you not only in my benefit, but to show you what you would do if D wasn't so obvious when you only find x.
