Plss can someone me with this problem and pls show work

-x-3=10 (combine like terms)

-x=13 (add 3 to both sides)

x=-13 (divide both sides by -1)

so you add 3 to the 10 since it is the opposite of a negative 3

then you subtract 6 from 13 since -6 it is the opposite of positive 6

then you divide both sides by -1

then it is x=-7

10% of increase is the final answer! : )