8 Times the sum of a number and 3​

This question is asking you to write the algebraic expression for "five times the sum of a number and 8).  Basically it is saying take a number (x) and add 8 to it. When we add, the answer is the sum.  

So the first part of the expression is (x + 8)

Then multiply that sum by 5

So our answer is 5(x+8)

maximum area = xy = (16)(32) = 512 ft2

to maximize the area of the garden, the side of the fence parallel to the side of the house should be 32 ft long, and the other two sides should both have length 16 ft.'

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