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

Question

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

zehanz · Answer

Subtract the second equation from the first to eliminate a, then calculate b. At last because you have b, you can also find a!

anonymous · Answer

I am confused math is not my best subject

zehanz · Answer

Do this:

(i)   a+7b=7
(ii)  a+2b=-3
      --------  -
(iii)      5b=10

Explanation:
a-a eliminates a
Also calculate 7b-2b=5b
Finally 7-(-3)=7+3=10

So now you have 5b=10.

Calculate b, then substitute that value in eq. (i) or (ii)

anonymous · Answer

would  it look something like this $$a + 7b= 7$$$$a + 2b = -3$$

anonymous · Answer

I hope I dont sound stupid here but when calculating for b would I reverse the numbers so it would like b+7a=7 and then b+2a=-3

zehanz · Answer

No, once you've found what b is (solve 5b=10), use that value to replace b in a+7b=7.

anonymous · Answer

oh ok

anonymous · Answer

a+7(10)=7