Answer:
m = 
Step-by-step explanation:
distribute parenthesis on both sides
ac + am = 2c + 6m ( collect terms in m on left side )
subtract 6m from both sides
ac + am - 6m = 2c ( subtract ac from both sides )
am - 6m = 2c - ac ( factor left side )
m(a - 6) = 2c - ac ( divide both sides by (a - 6))
m = 
30 x 0.75 = 22.5 .............(1st)
22.5 x 0.75 = 16.875 ......(2nd)
16.875 x 0.75 = 12.66 ....(3rd)
ANSWER: C) 12.66
For #7 - part a: greatest common factor (GCF) is 5.
Part b: cross out everything BUT 10 & 20.