**Q) **If the system of linear equations 2x+3y= 7 and 2ax + (a + b) y = 28 have infinite number of solutions, then find the values of ‘a’ and ‘b’.

**Ans:**

We know linear equations can be written as ax + by + c=0

Therefore, in given equations, 2x+3y=7 ——(1)

And, 2ax+ (a + b) y = 28 ——-(2)

In equation (1), let a_{1}=2; b_{1}=3; c_{1}=7

And in (2), let a_{2 }= 2a ; b_{2} = (a + b) ; c_{2} = 28

We know, when system of linear equations have infinite solutions, then

Therefore,

Solving equations separately, we get:

**a = 4 and b = 8**