What’s the answer to this please? Thanks!

The fence around a quadrilateral-shaped pasture is 3a^2+15a+9 long. three sides of the fence have the following lengths: 5a, 10a-2, a^2-7. what is the length of the fourth side of the fence?

You have 138.72 in your saving account u take out 45.23 and 18.00 you deposit 75.85 into your account

Sweet t saved 20 percent of the total cost of the green-eyed fleas new album let there be fleas on earth. if the regular price is $30 how much did sweet save