choice D
To factor a quadratic equation ax^2+bx+c, find two factors of a and write them in a column, one up, one down. Then find two factors of c and write them in a column. multiply the factors diagonally and add up the products to make b. if the products do not make b, switch the factors up down and try again till you have a match.
in this case,
-1 and 3 are the factors of -3, -5 and 1 are the factors of -15, -1 times 1 is 1, 3 times -5 is -15, -1 and -15 make a sum of -16. so you have (-1x-5)(3x+1)
take the negative sign out you have -(x+5)(3x+1)
I hope I've made myself clear.
