The cost of six filters is 29.94 since each filter costs 4.99
1/4 = 3/12
3/12 < 5/12
Therefore, 5/12 is greater than 1/4
If you find a first you will be able to find b a little faster then it is super easy after that you got this!
I am unsure about the very last problem but I can help with the first two
1) (y+1)+4
If we combine the numbers 1 and 4, we get +5 and can isolate the numbers from the variable.
This would give us

2) (6*r)*7
remember that we do not have to explicitly state 6*r
Instead, we can write it as 6r
this helps us get rid of the parentheses
now we can write it as

I hope this helps!:)