sample equation is 5(x-3)=a(x+4)+3x+b i want to know what the ideal process of solving an equation like this would be. i’m trying to find what “a” and “b” have to be to make this equation have infinit

sample equation is 5(x-3)=a(x+4)+3x+b

i want to know what the ideal process of solving an equation like this would be. i’m trying to find what “a” and “b” have to be to make this equation have infinitely many solutions. do i have to guess and check? or is the a better way to  find the values of the variables to make it infinitely many solutions