Question

If the lines given by ax - y = 3 and 21x - 3y = 9 will have infinitely many solutions, then the
value of a is......​

Answer 1

Answer:

a = 7

Step-by-step explanation:

A1/A2 = B1/B2 = C1/C2

this is condition 4 infinitely many solutions

A1 = a , A2 = 21 , B1 = -1 , B2 = -3 , C1 = 3 , C3 = 9

now B1/B2 = -1/-3 = 1/3 and

C1/C2 = 3/9 = 1/3

therefore, 4 this above condition value of A1/A2 must be equal to 1/3

so a = 7

A1/A2 = 7/21 = 1/3