I need the answers to these questions asap please and if you could provide steps it would be much appreciated thank you

Find the equation using the point (4,8)

I’m confused on how to work the pie charts

Serena is making an experiment. for that, she needs 20 grams of a 52% solution of salt. she has two large bottles of salt water: one with 40% and the other with 70% of salt in them. how much of each must she use to make the solution she needs? i am in need of