Question

If it says use the method of substitution to solve the system of linear equations


3a=6-b
3a=4-b

How do i find the solution

Answer 1

Well, you use substitution. To do substitution, you choose one of the equations, and express one of the variables in terms of the other.
Actually, here, we can see that the first equation (3a = 6-b) can be readily substituted to the second equation (3a = 4-b), because of they have the same term, 3a:
If 3a = 6-b, and 3a = 4-b also, then
6-b = 4-b
6 = 4
which cannot be. If you arrive at this kind of answer (constant 1 = constant 2), that means there is no solution for this particular system of equations.

hope this helps~ `u`