which is the right answer to 4x - 5 = 2x + 7?

it's the latter: x = 6. you have to change '+' into '-' and vice versa when moving from one side of the equation to the other.

x = 6!

To keep an equation equal you must modify the left and right sides the same way. So to move elements from one side to another you must add the opposite value. 1 + 5 = 2 + 4 to move the 5 over would be 1 + 5 + (-5) = 2 + 4 + (-5), which reduces to 1 = 2 + 4 - 5 or 1 = 1. Now you should be able to say which is correct.

The second one is right. x=6.

If you move a number to opposite side of equal, you have to multiply -1 to it.

x = 6

4x = 2x + 12 (add 5 to both sides)

2x = x + 6 (divide both sides by 2)

x = 6

to remedy for x, isolate it. while moving something from one area of the equation to the different, replace the sign, because of the fact what you do to a minimum of one area you do to the different. case in point you subtract 5 from the left area, you may desire to additionally subtract 5 from the main stunning, so once you do it directly the plus 5 on the left disappears and there's a subtract 5 on the main stunning area. -2x + 5 = 4x - 7 -2x - 4x = -7 - 5 -6x = -12 -6x/-6 = -12/-6 x = 2

The second one

4x - 2x = 7 + 5
2x = 12
x = 6

The idea in solving such equations is to get all the x elements one side and the numbers the other.

In your first attempt you have tried to add 2x to both sides and subtract 5 from both sides but that is not correct:

4x - 5 + 2x - 5 = 2x + 7 + 2x - 5 which would give:

6x - 10 = 4x + 2 which hasn't got you anywhere.

You second attempt is spot on. The answer is x = 6

4x - 5 = 2x + 7
4x - 2x = 5 + 7
2x = 12
x = 12/2
x = 6