Question

Identify the x-intercept(s) for: f(x) = x^2 + 3x − 4

Answer 1

umm

Answer 2

idk

Answer 3

lol

Answer 4

x-intercepts when y= 0 f(x) = 0
factor the quadratic

Answer 5

so (1,0) through (-4,0)

Answer 6

already general form
a = 1 b = 3 and c = -4
what is a*c
what are the factors that add up to b?
do you still want to go through the steps?

Answer 7

a*c=-4.

when you say add up do you mean multiply into b?

Answer 8

you need 2 numbers whose product is -4 and whose sum = 3

Answer 9

-4 and 1

Answer 10

if 2 numbers are a and b then
ab = -4
a+b = 3

Answer 11

The x intercepts is also the roots of the equation.

Answer 12

swap the signs

Answer 13

-4 + 1 = -3

Answer 14

so not those 2 numbers

Answer 15

so -1 and 4

Answer 16

right!

Answer 17

hokay thank you for working that out with me

Answer 18

now those 2 numbers give you the factors
x^2 +3x - 4 = 0
(x -4)(x +1) = 0

Answer 19

question though with the graph of this that was posted earlier it was -4 and positive 1 why did this switch?

Answer 20

oh sorry - i made a mistake
its
(x + 4)(x - 1) = 0

Answer 21

Alrights so basically the x-intercepts come from multiplying a*c and then finding what two numbers multiply into c and add into b?

Answer 22

having factored the function we now can find the values of x when f(x) is zero

Answer 23

- those 2 numbers do NOT give you the x-intercepts - they give you the values that go into the two factors

Answer 24

ok

Answer 25

so then what is the next step