Find the values of a and b for which the following system of linear equations has infinite number of solutions:

Question

Philoid · Accepted Answer

For infinitely many solution

⇒ 2a + 2b – 6 = 3a + 3b and 12a + 3b = 7a + 7b – 21

⇒ a + b = -6 ----- (1) and 5a – 4b = - 21 ------- (2)

Multiplying eq1 by 4 and adding to eq2

⇒ 9a = -45

⇒ a = -5

Thus, b = -1