a = –2 and b = 3
Solution:
Given equations are
3a – b = –9 – – – – (1)
–3a – 2b = 0 – – – – (2)
To solve these equations by elimination method.
Elimination method means eliminating one variable to find the other variable.
Add equation (1) with equation (2), we get
3a – b + (–3a – 2b) = –9 + 0
⇒ 3a – b – 3a – 2b = –9
Combine like terms together.
⇒ 3a – 3a – b – 2b = –9
⇒ 0 – 3b = –9
⇒ – 3b = –9
Divide by (–3) on both sides, we get
⇒ b = 3
Substitute b = 3 in equation (1), we get
(1) ⇒ 3a – b = –9
⇒ 3a – 3 = –9
Add 3 on both sides of the equation,
⇒ 3a = –6
Divide 3 on both sides of the equation
⇒ a = –2
Hence, a = –2 and b = 3.
