How do you use substitution to solve 3x - 2y = 2 and x = 3y - 11?

2 Answers
Jan 16, 2018

x=4
y=5

Explanation:

Substitution is done by choosing what variable has provided the easiest way to do the process. Since, the second equation x=3y-11; where value of x is already provided, it's convenient to solve the value of y first; that is,

3x-2y=2->eq.1
x=3y-11->eq.2

3x-2y=2
where x=3y-11, Now plug in the value of x

3(3y-11)-2y=2, distribution property

9y-33-2y=2, combine like terms

9y-2y=2+33, simplify the equation

7y=35. divide both sides by 7 to isolate the y

(cancel(7)y)/cancel(7)=(cancel(35)5)/cancel(7)

y=5

Now, find the value of x using the second equation and plug in the value of y=5:

x=3y-11

x=3(5)-11

x=15-11

x=4

Checking:

where: x=4 "and " y=5

Eq.1:
3x-2y=2
3(4)-2(5)=2
12-10=2
2=2

Eq.2:
x=3y-11
4=3(5)-11
4=15-11
4=4

Jan 16, 2018

7y-33 is the answer when you substitute x and simplify.

Explanation:

You substitute the x with 3y-11 and keep simplifying until you get the answer. Here are the steps:

3(3y-11)-2y=2

(Then you distribute/ multiply 3 by what's inside the parentheses.)

9y-33-2y=2

(It may seem like you have your answer, but not yet! Hmm... it seems like there are two "y's", huh?)

7y-33

(I just did 9y-7y)

7y-33 is the answer.


My source is my knowledge.
I hope that helped you!