What happens in a system of equations being solved by substitution if the "X"is canceled out

Question

For example :

2x+4=3x₂+2x+9

if i were to combine like terms the "2x" on the left would be canceled out by "-2x" what do i do in this situation?

Answer 1

After the 2x's cancel each other, you are left with

4 = 3x²+9

So you can still solve for x, but you will get an imaginary number, √-1 = i.

3x²=-5

x = ±√(-5/3) = ±i√(5/3)