You skipped a couple of steps
We started with this
3x+4 = -8
Then we wanted to get the +4 off of the left side so we
add -4 to both sides like this
3x+4 = -8
-4 = -4
Then we draw a line:
3x+4 = -8
-4 = -4
----------
Then we bring down the 3x, we don't write anything under
the +4 and -4 because they cancel. We bring down the
= sign and we combine -8 and -4 and get -12.
3x+4 = -8
-4 = -4
----------
3x = -12
You skipped that step. Next we want to get rid of the 3.
That is a multiplied 3, so we will need to divide both
sides by 3, to do that we put a fraction bar under each side
and put a 3 as a denominator, like this
3x+4 = -8
-4 = -4
----------
3x = -12
3x -12
———— = —————
3 3
You also skipped that step. Now the 3's cancel and just leave
an x on the left, and we divide the -12 by 3 and get -4
3x+4 = -8
-4 = -4
----------
3x = -12
3x -12
———— = —————
3 3
x = -4
----------------------------------
We start with this:
2(x+7) = 5x+14
Use the distributive property to remove the parentheses on the left:
2(x+7) = 5x+14
2x+14 = 5x+14
Next we add -14 to both sides and draw a line:
2(x+7) = 5x+14
2x+14 = 5x+14
-14 -14
--------------
Now we bring down the 2x, the +14 and -14 cancel so we don't
write anything there, then we bring down the = sign, then the
5x and we don't write anything at the end because that +14 and
-14 also cancel:
2(x+7) = 5x+14
2x+14 = 5x+14
-14 -14
--------------
2x = 5x
Next we add -5x to both sides to get the 5x off the right side.
2(x+7) = 5x+14
2x+14 = 5x+14
-14 -14
-------------
2x = 5x
-5x = -5x
We draw a line
2(x+7) = 5x+14
2x+14 = 5x+14
-14 -14
-------------
2x = 5x
-5x = -5x
--------------
We combine the 2x and the -5x and get -3x, we bring
down the = sign, now ordinarily we wouldn't write anything under
the right side since 5x and -5x cancel, but we MUST NEVER
LEAVE a side of the equation EMPTY! So we must put a 0 there:
2(x+7) = 5x+14
2x+14 = 5x+14
-14 -14
--------------
2x = 5x
-5x = -5x
---------------
-3x = 0
Next we want to get rid of the -3.
That is a multiplied -3, so we will need to divide both
sides by -3. To do that we put a fraction bar under each side
and put a -3 as a denominator, like this
2(x+7) = 5x+14
2x+14 = 5x+14
-14 -14
-------------
2x = 5x
-5x = -5x
--------------
-3x = 0
-3x 0
———— = —————
-3 -3
Then the -3's cancel on the left. On the right
we are simply dividing 0 by -3 and that just
gives us 0. So the whole thing worked out is:
2(x+7) = 5x+14
2x+14 = 5x+14
-14 -14
-------------
2x = 5x
-5x = -5x
--------------
-3x = 0
-3x 0
———— = —————
-3 -3
x = 0
Edwin
