Inequalities math question?

Question

Ok I'm having a little trouble with my math homework which is dealing with inequalities so here's the question.....

63 + [3d - 12] = 21

Answer 1

- 63 both sides  |  3d -12  |  = -42

since | a| =b   can be either - b or + b

3d -12 = -42  and  3d-12 = +42

3d =-30         and       3d=54

d = -10 and d=18

check   -30-12= -42     and 3*18-12 = +42

Answer 2

Ok so first you need to get the D by itself.Start with the 63 on the left.Since it's a positive, you should do the opposite(subtract).So now you do 21-63,giving you -42 on the right side.Now let's get the 3 out of the way.It's multipled with the D so divide 3 with -42.Giving you -14.Now we have a new problem. d-12=21. Add 12 to 21 and you get 33. d=33 .

Answer 3

1. Minus 63 from both sides.

2. Add 12 to both sides.

3. Divide both side by 3 (from the 3d).

4. d = -10

Answer 4

63 + [3d - 12] = 21

-63                   -63

3d-12=-42

    +12 +12

3d=-30

/3    33

d= -10

Answer 5

I dont feel like explaining it so go here it might help ya out.

http://www.purplemath.com/modules/ineqso...

Answer 6

63+ (3d - 12) = 21

-63                  -63

       3d - 12 = -42

           +12    +12

       3d       = -30

       ---           -----

        3                 3

        d        =  -10