Question

I have to solve the system
7x - 3y = 20
5x + 3y = 16
I solved it once;
7x - 3y = 20
+ 5x + 3y = 16
= 12x = 36
= x = 3
7(3) = 3y = 20
= 21 - 3y = 20
21 - 21 - 3y = 21 - 21
= 3y = -1
= y = 1/3
so (3, 1/3)
But I cant figure out how to solve it for a nother way and get the same answer.

Answer 1

Example:
2X+6Y=10
3X-2Y=12

There is another method called substitution, in which you manipulate one of the equation to isolate a variable. For example 2X+6Y=10 can be manipulated into X=5-3Y
Then you substitute the second part of the equation, 5-3Y in the second equation, 3X-2Y=12, resulting in 3(5-3Y)-2Y=12. Then you can use simple algebra to figure out X and Y

Answer 2

I know about substitution, and I have attempted it several times in several different manners but I cannot come up with the same answer as the first.

Answer 3

If at all.

Answer 4

There's at least five different ways of solving these

1. Graphing
2. Substitution
3. Elimination
4. Matrices
5. Cramer's Method

Pick one

Answer 5

There's also slope-intercept method as well