A salesperson at a jewelry store earns 9% commission each week. Last week, Heidi sold $640 worth of jewelry. How much did she make in commission? How much did the jewelry store make from her sales?

the sum of all the angles in a triangle are equal to 180

so you can add   the 3 given angles together to equal 180:

5y + 2y + 2y = 180

or since all three angles have the same letter, combine the 3 angles to equal 180:

9y = 180

the answer is 844

step-by-step explanation:

it is 844 because if you add 836.50 + 7.5 you will get 844

12r - 8 - 12

you have to combine like terms. below i have bolded the like terms:

12r - 8 - 12

together it combines to:

12r - 20

hope this !