you want to use PEMDAS which is parenthesis exponents multiplication division addition subtraction and work your way from left to right. so 15+42=57 and then 24-9=15 and 81-15=66 hope this helped :)
Check your solution by first checking the end point , in the related equation. Pick a value greater than , such as 2, to check in the inequality. Solve for x. Divide both sides by 3 to isolate the variable.
