Question

Find the zeros of each function by using a graph and a table f(x)=x^2+3x-18.

Answer 1

1) Finding the zeros of this function f(x) =x² +3x -18

f(x) = x²+3x-18 Factoring this equation, and rewriting it

Which two numbers whose sum is equal to 3 and their product is equal to 18?

6 -3 = 3 and 6 *-3 = -18

So we can rewrite as (x +6) (x-3)

(x+6)(x-3)=0 Applying the Zero product rule, to find the roots

x+6=0,

x=-6

x-3=0,

x=3

S={3,-6}

2) Setting a table, plugging in the values of x into the factored form: (x-6)(x-3)

x | y |

1 | -14 (1 +6)(1-3) =-14

2 | -8 (2 +6)(2-3) =-8

3 | 0

4 | 10

-5 | -8

-6 | 0

3) Plotting the function: