Answer:
Step-by-step explanation:
9(c+7)=27
9c+63=27 subtract 63 from both sides
9c= -36 divide by 9
c= -4
3(2r-8)+4r=76 foil
6r-24+4r=76 combine like terms
10r-24=76 add 24 to both sides
10r+100 divide by 10
r= 10
