Eight times the difference of a number and nine is the opposite of eight

I'm in trigonometry so it's been a while since i've been in algebra 2 but i believe that the answer is n = 10 *where n equals a number*

if you are multiplying 8 times the difference of a number and 9, you first of all will write the nine first. so it will look like 8(9-n) because the 8 is being multiplied by the whole expression.
the opposite of 8 is -8 so the expression would then change to the equation
8(9 - n) = -8 
you then will simplify by first distributing the 8 ( changing the equation to 72-8n ), then subtracting the 72 from both sides ( -8n = -80 ) and then diving -8 from -80 leaving n = 10.

hope this helped :)