Question

Solve the system of equations using the Addition method.

2a + 3b = -1
3a + 5b = -2


The addition method tells you to find common multiples of a coefficient, then add the equations together to eliminate a variable.
If you multiply the first equation by 3 and the second by -2 you have
2a + 3b = -1
3a + 5b = -2
becomes
3 (2a + 3b = -1)
-2(3a + 5b = -2)
which is
6a + 9b = -3
-6a-10b = 4
Now add together to get
-b=1 or b=-1
Now substitute into either equation and solve for a.