Question

Solve the system of linear equations using linear combination.

3a + 6b = 45
2a – 2b = –12
  Which is the solution to the system?

Answer 1

The answer is (1,7). Hope it helps

Answer 2

3a + 6b = 45
2a - 2b = -12....multiply by 3
----------------
3a + 6b = 45
6a - 6b = - 36 ...(result of multiplying by 3)
---------------add
9a = 9
a = 1

3a + 6b = 45
3(1) + 6b = 45
3 + 6b = 45
6b = 45 - 3
6b = 42
b = 7

solution is : (1,7)