Question

Solve for x: -3|x + 7| = -12

Answer 1

Those lines just mean that the x+7 is positive so just think of it as parentheses. Distribute the -3 in (x+7).

Answer 2

You should get -3x-21.

Answer 3

-3x-21=-12

Answer 4

Now try to solve this.

Answer 5

It should be easier.

Answer 6

x-18=-12

Answer 7

right???

Answer 8

Ya.

Answer 9

x=6

Answer 10

Then the answer would be x=6. But you aren't done there. When I told you that the absolute value is like parentheses, I was trying to not confuse you by saying that now you have to put a negative in front of the parentheses.

Answer 11

Absolute values will always be positive and negative when it comes to equations.

Answer 12

you should get two answers
first divide both sides by -3
|x+7|=4
you have to solve both equations below:
x+7=4 or x+7=-4

Answer 13

So now it should look like this(-3){-(x+7)}=-12

Answer 14

then both by -11

Answer 15

-3(-x-7)=-12
3x+21=-12
3x=-21-12
3x=-33
x=-11

Answer 16

Yes that's the second answer.

Answer 17

x=6 gives a false equation
-3|6+7|=-12 doesn't hold
-3|13|=-12
-3(13)=-12
-39=-12 see this isn't the same thing on both sides so x=6 isn't a correct solution

Answer 18

thxs i got my answers you guys are the best

Answer 19

I don't think it's suppose to equal back to the problem @freckles. Look at this link. http://www.purplemath.com/modules/solveabs.htm

Answer 20

And you're welcome!

Answer 21

yes it is
in order for x=c to be a solution it must satisfy the equation

Answer 22

the first equation was just solved incorrectly

Answer 23

When you plug in the 1st x of the equation from the picture. It doesn't equal 7. The second x does though.

Answer 24

-3(x+7)=-12
-3x-21=-12
add 21 on both sides
-3x=-12+21
-3x=21-12
-3x=9
divide by -3 on both sides
x=-3

as you see pluggin x=-3 into original this does satisfy initial equation

-3|x+7|=-12
replace x with -3
-3|-3+7|=-12
-3|4|=-12
-3(4)=-12
-12=-12 this is a true equation
so x=-3 is a solution

just like x=-11 is also a solution since
-3|x+7|=-12
pluggin in -11 for x
-3|-11+7|=-12
-3|-4|=-12
-3(4)=-12
-12=-12 same thing on both sides the equation is true
x=-11 is also a solution


so the solution set is {-3,-11}

Answer 25

@200205650 you have to plug into the original equation

Answer 26

Okay then never mind. You are right.