Can someone see if I did this right please (:

3(10x+12)=15x+3

30x+36=15x+13

-15x      -15x

15x+36=13

      -36   -36

Then i divided, which got mee...

X=-1.5

Solve for x:
3 (10 x+12) = 15 x+13

3 (10 x+12) = 3 (10 x)+3 12:
3 10 x+3 12 = 15 x+13

3×12  =  36:
3 10 x+36 = 15 x+13

3×10  =  30:
30 x+36 = 15 x+13

Subtract 15 x+13 from both sides of 30 x+36 = 15 x+13:
30 x-15 x+13+36 = (15 x+13)-15 x+13

(15 x+13)-(15 x+13) = 0:
30 x-(15 x+13)+36 = 0

-(15 x+13) = -13-15 x:
30 x+-13-15 x+36 = 0

Grouping like terms, 30 x-15 x-13+36 = (30 x-15 x)+(36-13):
(30 x-15 x)+(36-13) = 0

30 x-15 x = 15 x:
15 x+(36-13) = 0

36-13 = 23:  15 x+23 = 0
Answer: |  - 23/15

Omggg. :(

I cant do math!

3(10x+12)=15x+13

My answer i got was..

X=-1.5

This is how oyu check your answer.

LHS = 3(10*-1.5+12) = 3( -15+12) = 3*-3 = -9

RHS= 15*-1.5+13 = -22.5+13 = -9.5

No they are not the same.  So one of us did someting wrong :(

Show us your working so we can explain what you are doing wrong :)

NOTE: you can also check your answers to equations like this using the web2 calc.

Just put your equation into the input line and press =.

BUT you do need to know how to check it by hand as well, and you will not remember if you do not practice it a lot of times :)

Yes you CAN do maths Miss Hayley !!

You just have to practice a lot.

15x+36=13

      -36   -36

15x     =  -23                            [you seemed to have left this bit out :/ ]

divide both sides by 15 and you get

x= -23/15

Oh. Was I suppose to put it as a fraction, instead of a decimel?? :)

Oh. Was I suppose to put it as a fraction, instead of a decimal?? :)

I should really have written the final answer as a mixed numeral or an exact decimal

It doesn't really matter so long as your answer is exact - your answer was not exact!

My answer  was  -23/15

the best answers would be

\(-1\frac{8}{15}\qquad or \qquad -1.5\dot3\)

oh, okay!

Great!!

Thanks for your help :)

And thank you too, Guest!!