Because you have to go in the order of PEMDAS, parenthesis, exponents, multiplication, division, addition, and subtraction. From what you are saying, 'why you must simplify 3 to the second power first' it seems that you have no parenthesis, so you move onto what is next, which is exponents, in this case, 3 to the power of two.
Answer:
B.) StartFraction 5 StartRoot 11 EndRoot + 5 StartRoot 3 EndRoot Over 8 EndFraction
Step-by-step explanation:
edge 2020
The distributive property: a(b - c) = ab - ac
27 - 18r = 9·3 - 9·2r = 9(3 - 2r)