Question

Solve the system of linear equations using linear combination.

Answer 1

Answer:

a = 1, b = 7

Step-by-step explanation:

Given the 2 equations

3a + 6b = 45 → (1)

2a - 2b = - 12 → (2)

Multiply (2) by 3 and add to (1) to eliminate the term in b

6a - 6b = - 36 → (3)

Add (1) and (3) term by term

(3a + 6a) + (6b - 6b) = (45 - 36)

9a = 9 ( divide both sides by 9 )

a = 1

Substitute a = 1 in either (1) or (2) and solve for b

(1) → 3 + 6b = 45 ( subtract 3 from both sides )

6b = 42 ( divide both sides by 6 )

b = 7