Question

4(1.25y+4.2)<16.8

Answer 1

therefore do
1.25y+4.2 < (16.8)/4
1.25y < (16.8)/4 - 4.2
y < ((16.8)/4 - 4.2)/1.25
do you see why?

Answer 2

no

Answer 3

you basically divide, so you can access the middle, then minus to get rid of the 4.2 then divide to get rid of the 1.25.....