Please Answer.. Thank You.. 

Since this equations are having infinte solution then there ratios will be 
a₁/a₂ = b₁/b₂ = c₁/c₂
here if we apply the co-efficient 

2a−1/3​=3/b-1=-5/2
2a-1/3=3/b-1=5/2

then,
2a-1/3 = 5/2  
4a-2 = 15
a= 17/4

and 
3/b-1 = 5/2
6 = 5b-5
5b = 11
b=11/5