If a > 0 > b, show that 4 - 5ab + > 0

Ascuba diver was 80 feet below sea level and swam up at a rate of 4 feet per minute. the two solutions show how long it took the scuba diver to reach an elevation of 20 feet below sea level. lydia and max used the methods shown below to find the time it took the diver to reach the new elevation.

Ineed to know the answer to this algebra question.

Evaluate the discriminant of each equation. tell how many solutions each equation has and whether the solutions are real or imaginary. 4x^2 + 20x + 25 = 0