How would you cancel the 2x in the equation: 4x + 3 = 2x + 12

To cancel 2x, you need to do the 'inverse' to the other side.

4x+3= 2x+12

You would subtract 2x (on both sides) since it is a positive number. It is all about balance.

4x (-2x) +3= 2x (-2x) + 12

2x+3= 12 I will go ahead and solve for x.

Subtract 3 on both sides. (3 is positive)

2x= 9

Divide both sides by 2. (2 is being multiplied by x; do the inverse)

x= 4.5

We can always check our answer by plugging 4.5 in as x.

4(4.5)+3= 2(4.5)+12

21= 21

I hope this helps!
~kaikers

Subtract three from both sides.
4x = 2x + 12 - 3
Simplify that
4x = 2x + 9
Subtract 2x from both sides
2x = 9
Simplify
x = 9/2 or 4.5