The distributive property....ur basically multiplying the number outside of the parenthesis by everything in the parenthesis....to get rid of the parenthesis.
9(2 + 5m) = (9 * 2) + (9 * 5m) = 18 + 45m <==
I believe $1, two of the friends left, if it's not the correct answer I'm sorry.
Look a view at this picture
1.Simplified each one
2/5 (both divided by 7) , 1/2 (divided by 21)
2.Make them into integer
(2/5 )*(2/2)=4/10 , (1/2)*(5/5)=5/10
Now the dominators are the same ,you can just compare the numerators. It is 4:5