89.9k views
2 votes
X+y=20
x=-4+y how do i solve this equation by using substitution

User Duri
by
7.7k points

1 Answer

3 votes

Answer:

The solutions is (8,12).

Explanation:

The second equation is solved for x so we can replace the first x in the first equation with what the second x in the second equation equals.

That is we can do this:

x+y=20 where x=-4+y

(-4+y)+y=20

-4+y+y=20

Combine like terms:

-4+2y=20

Add 4 on both sides:

2y=24

Divide both sides by 2:

y=24/2=12

So if x=-4+y and y=12, then x=-4+12=8.

The solution is (8,12).

This means that (8,12) is a common point on both the given equations.

This means it will make both equations true when plugging it in.

x+y=20 with (x,y)=(8,12):

8+12=20 is true since 8+12 is 20.

x=-4+y with (x,y)=(8,12):

8=-4+12 is true since -4+12=8.

User Yao Li
by
8.5k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories