Possible rational roots of 4x^2+15x-54=0

Jasmine wants to eat at 8: 00pm her meal takes 65mins to cook what time does she need to put the meal in the oven

Evaluate the expression for the given value of the variable. | ? 4 b ? 8 | + ? ? ? 1 ? b 2 ? ? + 2 b 3 -4b-8+-1-b2+2b3 ; b = ? 2 b=-2

Having a hard time understanding this question (see attachment).