7.D is the correct answer. I simplified 12/27 to 4/9 then i try to see if 4/9 is equivalent to 20/45 and it is you multiply 4 and 9 by 5= 20/45
8. 1.4*2.1=2.94 then 2.94/1.5= 1.96 so c=1.96
9. Explanation You multiply- 5/8 * 3/5 then divide = answer divided by 2/3
Solving: 5/8*3/5= 3/8 then 3/8 divided by 2/3, flip second number and then switch the division sign to multiplication sign so it should be like this : 3/8 * 3/2= 9/16
answer= 9/16