Product Sum II
These examples will help you to use the product-sum in trinomials (ax2+bx+c)when the b or c value is negative. Remember sometimes you will have negative factors.
ex. x2+5x-14 p= -14
s= 5 factors are +7 and -2
so factored expression is (x+7)(x-2)
ex. x2-4x+3=0 p= 3
s= -4 factors are -3 and -1
(x-3)(x-1)=0 use zero product property to solve
x= 3 or 1
ex. The ALG-I rocket follows the path of h = t2-30t+225. If h is the height
of the rocket and t is the time in minutes the rocket is in the air, how long
would the rocket have traveled for when it came back to earth?
t2-30t+225=0 p= 225
s= -30 factors are -15 and -15
(t-15)(t-15)=0 so t=15 minutes