Decide whether the given number is a solution of the given equation. I did I do this problem right?

Question

Is 9 a solution of -x - 3 = -12?

I did this problem like this

9x-3= -12

9x + 3 =+12

9(3)

27+3

30 = +12

Did I do this right so far?

Answer 1

Yes, 9 is an answer. The full solution would be as follows:

-x - 3 = -12
-x - 3 +3 = -12 + 3 (add 3 to each side)
-x = -9
(-x) X (-1) = (-9) X (-1) (multiple each side by -1)
x = 9

Your error in your solution is that you multiple x by 9 rather than substituting 9 for x and then testing the answer.

Answer 2

No. You're supposed to replace x with 9. So -x - 3 = 12 becomes
-9 - 3 = 12.

If this is true, then it is a solution.

Answer 3

Is 9 a solution of -x - 3 = -12?

Cking whether you have a valid solution is easier than having to find the solution.

Plug 9 into the LHS: -(9) - 3 =-12

Plug 9 into the RHS: (Rather easy! Nowhere to plug in.) -12

Since x = -9 makes the LHS = RHS then you have a valid solution.

Answer 4

To solve - x - 3 = -12
IF you wanted to convert it all to +, then you'd have to multiply the entire side of the equation (and both sides) by -1, like so:
-1 (-x -3) = -1 ( -12)
which:
x + 3 = +12
x = 9

Test: - 9 - 3 = -12

Hint: Anytime you wish to change + to - or vice versa, always multiply BOTH sides (and the entire side) by -1, don't use any other numbers but -1, it's the easiest way.

Answer 5

I show you my solution

-x-3 =12

multiply by -1

x+3 =-12

x = -9

check -9-3 =-12

Answer 6

-x-3=-12

multiply by -1

x+3=12
x=9

thus 9 is a solution

Answer 7

You done good, sorta.

Right answer, wrong technique.
x = -9 so
-9 -3 = -12 which is

Answer 8

First, you would possibly want to unravel for f. you could do this by including f to each section, so that you get -9f+f=sixty 4. Then, component out the f, so that you get f(-9+a million)=sixty 4. Then, you get f(-8)=sixty 4. sixty 4/-8 = f, so f=-8. you could confirm it any opposite direction too. -9f=sixty 4-f -9=sixty 4/f-f/f -9=sixty 4/f-a million -8=sixty 4/f