Question 72712
Find the solution to the equation:  
Perform the necessary operations to get the variable on the left and the numbers on the right
:
6x - 3 = -2x + 21
:
Add 2x to each side:
6x + 2x - 3 = -2x + 2x = 21
8x - 3 = 21
:
Add 3 to each side;
8x -3 +3 = 21 + 3
8x = 24
:
Divide both sides by 8
(8/8)x = 24/8
1x = 3
or just
x = 3, just like you said
:
But you can be sure of your solution. Substitute 3 for x in the original
equation and see if it is true:
  6x - 3 = -2x + 21
6(3) - 3 = -2(3) + 21
18 - 3 = -6 + 21
15 = 15 proves your solution, 
:
do this for all your solutions and you will know for sure you're right.