What number needs to be added to both sides of the equation in order to complete the square? x^2+16x=18

I'm terrible at math any here is appreciated.

Which best describes the transformation that occurs in the graph? a) dilation b) reflection c) rotation d) translation

An equation representing lyle’s hedge-trimming business is a = 12n - 300 where a is the amount of profit or loss in dollars and n is the number of hedges trimmed. how would the graph of lyle’s business change if the equation a = 10n - 300 represented his business? the graph would be flatter. the graph would be steeper. the graph would start closer to the origin. the graph would start lower on the y-axis.