Hello there!
To solve for m, the first thing you need to do is to add 8 to both sides. This would result in this: 9(8m+3)=675
Now that you have removed any constants that are not being multiplies, divide both sides by 9 to isolate the expression inside the parentheses. This would result in the equation 8m+3=75
When you have done that, subtract both sides by 3 in order to isolate the term 8m. This would result in 8m=72. Finally, to solve for m, divide both sides by 8 to result in your answer: m=9 :)