Question

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

Answer 1

subtract the 2 equations, what u get ?

Answer 2

I am sorry don't understand

Answer 3

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

Answer 4

b=5/4?

Answer 5

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

Answer 6

9b=4

Answer 7

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

Answer 8

so b=5/10?

Answer 9

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

Answer 10

still confused

Answer 11

on which step ?

Answer 12

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

Answer 13

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

Answer 14

ok now i understand

Answer 15

so the final answer would be 2

Answer 16

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

Answer 17

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 :)