<PRE><B>Question 214650</B>
How do I solve by addition method?
12x - 11y = -31
 5x + 7y =  45
:
Multiply the 1st equation by -5
Multiply the 2nd equation by 12
:
-60x + 55y = 155
+60x + 84y = 540
-------------------addition eliminates x
139y = 695
y = {{{695/139}}}
y = 5
:
Use the 2nd equation to find x, substitute 5 for y:
5x + 7(5) = 45
5x + 35 = 45
5x = 45 - 35
5x = 10
x = {{{10/5}}}
x = 2
:
:
Check solutions in the 1st equation
12(2) - 11(5) =
24 - 55 = -31</PRE>