Solve for x and check your solutions

-3+2x=-x+6

-3 + 2x = - x + 6 Add x to both sides

-3 + 3x = 6 Add 3 to both sides

3x = 9 Divide both sides by 3

x = 3

-3 + 2x = - x + 6 Plug in 3 for all of the x's

-3 + 2 (3) = - 3 + 6 Multiply 2 and 3

-3 + 6 = - 3 + 6

Since both sides of the equation are the same you know that 3 made the equation equivalent.