How do I change 2y = 3x + 8 into slope-intercept form?

Ican figure out 20 shares multiply by $117.98 =2359.6920 shares multiply by $124.32=2486.40then take 40 shares multiply by $128.48=5139.20after that i'm lost any be greatly appreciated.

The holiday party will cost $160 if 8 people attend.if there are 40 people who attend the party, how much will the holiday party cost

Alex measured the length of an item to be 3.7 cm. the actual length is 3.5 cm. what is alex’s percent error?