What number must be added to the expression below to complete the square? x^2+7x

Complete the steps, which describe how to find the area of the shaded portion of the circle. find the area of the sector by multiplying the area of the circle by the ratio of the to 360. subtract the area of the triangle from the area of the sector.

Which number produces an irrational number multiplied by 1/3

Im so bad at fractions they are not my best math thing to work on