Answer :

luana
[tex]x-\ number\\\\ 3x-10=x+4\ \ \ | subtract\ x\\\\ 2x-10=4\ \ \ | add\ 10\\\\ 2x=14\ \ \ | divide\ by\ 2\\\\ x=7\\\\ Number\ is \ 7.[/tex]
AL2006

The variable is "the number".  To make it easier to write the equation
and work with it, let's call the variable 'M' for 'Mystery number'.

3 times the number is 3M .

-- 10 less than that is  3M-10 .
-- the number plus 4 is  M+4

The question says that these two things are the same.
So ...
                                              3M - 10  =  M + 4

Subtract 'M' from each side:    2M - 10 = 4

Add  10 to  each side:              2M      = 14

Divide each side by 2 :              M  =  7