217k views
2 votes
Help meeeee doooo thissss

Help meeeee doooo thissss-example-1
User Krosshj
by
8.6k points

1 Answer

6 votes

Answer:

B: x=-5 and x=4

Explanation:

f(x)= x^2 + x -20

To find the zeros we replace f(x) with 0


0= x^2 + x -20

now we solve for x

LEts factor x^2 + x -20

sum is +1 and product is -20

5 * (-4)= -20

5 + (-4) = +1

x^2 + 5x - 4x - 20 = 0

(x^2 + 5x)+(- 4x - 20) = 0

x(x+5) -4 (x+5) = 0

(x-4)(x+5)=0

Set each factor =0 and solve for x

x- 4 =0 so x=4

x+5 =0 so x=-5

x=-5 and x=4

User Nick Kirsten
by
8.5k points

Related questions

asked Jan 6, 2017 171k views
Renan Gemignani asked Jan 6, 2017
by Renan Gemignani
7.6k points
1 answer
5 votes
171k views
asked Jun 2, 2020 138k views
Cephus asked Jun 2, 2020
by Cephus
8.0k points
1 answer
2 votes
138k views
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.