8(c - 9) < 13
First, distribute 8 to all terms within the parenthesis
8(c - 9) = 8c - 72
8c - 72 < 13
Next, isolate the c. Do the opposite of PEMDAS. Add 72 to both sides
8c - 72 (+72) < 13 (+72)
8c < 85
Divide 8 from both sides
8c/8 < 85/8
c < 85/8
c < 10.625
c < 10.625 is your answer
hope this helps