How do you factor the trinomial r^2 + 15r + 54 = 0?

2 Answers
May 30, 2018

(r+6)(r+9)

Explanation:

"the factors of + 54 which sum to + 15 are + 6 and + 9"

r^2+15r+54=(r+6)(r+9)

May 30, 2018

r^2 + 15r + 54 = (x+6)(x+9)

Explanation:

r^2 + 15r + 54

find two number that have a product of 54 and a sum of 15:

1 + 14
2 + 13
3 + 12
4 + 11
5 + 10
6 + 9 works!

Factors are:

(x+6)(x+9)

x=-6 and x=-9 as this graph of the function shows:

graph{x^2 + 15x + 54 [-16.59, 3.41, -4.4, 5.6]}