How do you solve literal equations like 4y+x=40 and y=-3+2/3

Fredrick designed an experiment in which he spun a spinner 20 times and recorded the results of each spin

Tabby sells clothing at a retail store, and she earns a commission of 6.25% on all items she sells. last week she sold a pair of jeans for $32.50, a skirt for $18.95, and 2 blouses for $14.95 each. what was tabby's total commission? a $4.15 b $5.08 c $81.35 d $348.60

How can (square root of 25) ^2 be rewritten?