Explain with example of why 2^(-8) * 2^(-7) is equal to 2^(-15)

Sole the equation 6n + 9 = -3n - 21 - 6 for n

Your company will replace the asphalt roofs on all the buildings at the factory complex shown below. the buildings have flat roofs. you charge according to the total roof area. what is this area, in square yards?

F(x) = 2x + 1? h(x) = x – h(x) = x + h(x) = x – 2 h(x) = x + 2