Question

If the pair of linear equations 3x + ay = 50 and 9x – 21y = 15 are parallel then find the value

of ‘a​

Answer 1

a1/a2 = b1/b2 ≠ c1/c2

3/9 = a/-21

1/3 = a/-21

a = -21/3

a = -7

Answer 2

Answer is -7

Step by step explanation is attached above...