## Jasmineplayhouse 2 years ago use the elimination method to solve the system of equations. a+7b=7 a+2b=-3

1. hartnn

subtract the 2 equations, what u get ?

2. Jasmineplayhouse

I am sorry don't understand

3. hartnn

let me give you an example on how to subtract equations, let the 2 equation be say, 2x+3y =7 2x-3y =2 now if i subtract the 1st equation from 2nd equation, i get (2x-3y) - (2x+3y) = 2-7 so, 2x-2x-3y-3y=-5 0-6y=-5 so, y = 5/6 in same manner, you try for your question of a+7b=7 a+2b=-3

4. Jasmineplayhouse

b=5/4?

5. hartnn

very close,but its 7b-2b = 7-(-3) can you proceed ?

6. Jasmineplayhouse

9b=4

7. hartnn

7-2 = 5 7- (-3) = 7+3 =10 -_-

8. Jasmineplayhouse

so b=5/10?

9. hartnn

7b-2b = 7-(-3) 5b = 10 b=10/5 = 2 got this ?

10. Jasmineplayhouse

still confused

11. hartnn

on which step ?

12. Jasmineplayhouse

7-(-3) since it has a minus sign in front i believed it was to be subtracted not added.

13. hartnn

- * - = + so, 7 - (-3) became 7+3

14. Jasmineplayhouse

ok now i understand

15. Jasmineplayhouse

so the final answer would be 2

16. hartnn

b=2 you still need to find 'a' put b=2 in any 1 of the original equation to get a

17. kelliegirl33

multiply the first equation by a -1. Doing this will cancel out the a's. You can then solve for b. Once you have solved b, substitute that in for b in either of the original equations and you will solve a. You can then check your answer by subbing in known variables in either of the original equations and if they equal, your answers are correct :)