There’s actually two questions on here please help me

Problem 7

Time is always an independent variable because time marches on doing its own thing without depending on external forces, or other people/things. Instead, other variables depend on time. In this case, the distance d depends on the independent variable t for time.

If the time goes up by 1 hour, then the distance variable goes up by 3 miles. In short, that tells us his speed is 3 mph.

Choice A) independent = time; dependent = distance

Problem 8

Everywhere you see an x, replace it with 9. Then use PEMDAS to simplify

f(x) = 5x - 9

f(9) = 5(9) - 9 ... x replaced with 9

f(9) = 45 - 9

f(9) = 36

36

78.59 is the mean

step-by-step explanation: