What is the slope of the line represented by -3x + 5y = 20 ?

I’m still confused on how to work the percentages

Jane’s favorite fruit punch consists of pear, pineapple, and plum juices in the ratio 5: 2: 3. how many cups of pear juice should she use to make 20 cups of punch?

Divide. –4.2 ÷ 6 = a –0.7 b 0.7 c –7 d 7 me