The altitude of an airplane is decreasing at a rate of 42 feet per second. what is the change in altitude of the airplane over a period of 25 seconds?

In what form is the following linear equation written y=9x+2

For problems 29 - 31 the graph of a quadratic function y=ax^2 + bx + c is shown. tell whether the discriminant of ax^2 + bx + c = 0 is positive, negative, or zero.

Which expression gives the exact value of x?