Write 5 - (-7) as an addition equation 5 - (-7) = 5 + ___

Based on what i know about mean, this doesn't add up.

Which of the following is true for the relation f(x)=2x^2+1

Anew landowner is interested in constructing a fence around the perimeter of her property. her property is 1,080√30 feet wide and 500√20 feet long. what is the perimeter of the property? (recall that the perimeter is the sum of each side of a shape or boundary). a 1,580√40 feet b. 5,320√5 feet c. 3,160√20 feet d. 10,640√5 feet