The answer is c
Because if it takes 50 minutes to run 4 miles you need to divide 50/4 and you will get 12.5 and then multiply that by 30 cause she is trying to run 30 miles and that will get you 375 and then divide that by 60 cause their are 60 minutes in a hour and you will get 6.25
Any number times 0 is going to equal 0
Perhaps the most concise way to factor is by "completing the square" which is how the quadratic formula is derived...
x^2+6x+8=0 move constant to other side, subtract 8 from both sides
x^2+6x=-8, halve the linear coefficient, square it, then add that to both sides, in this case (6/2)^2=3^2=9
x^2+6x+9=1 now the left side is a perfect square of the form
(x+3)^2=1 take the square root of both sides
x+3=±√1 subtract 3 from both sides
x=-3±√1
x=-3±1
x=-4 and -2
Since the zeros occur when x=-4 and -2 the factors of the equation are:
(x+2)(x+4)