Question

f(x) = 3x3 + 12x2 + 3x - 18 @jim_thompson5910

Answer 1

What are the zeros of that function? :) I found 1 as one of them, but I want to be sure if there are more.

Answer 2

which one did you find?

Answer 3

equate the equation to zero and factor

Answer 4

A. -1
B. 1
C. 2
D. 3

Answer 5

so what you can do is plug each into the function and see which one(s) give a result of 0

Answer 6

simple example: g(x) = 2x + 4

x = -2 is a zero or root of g(x) because

g(x) = 2x + 4

g(-2) = 2(-2) + 4 ... replace x with -2

g(-2) = 0

we get an output of 0, so the input x = -2 is a root. This corresponds to an x-intercept of (-2,0).

Answer 7

-2 is not in the answer choices.

Answer 8

it's my example

Answer 9

@jim_thompson5910 I tried all the answer choices, none worked for me.

Answer 10

I plugged x = -2 into my example function. Try the same with your answer choices.

Answer 11

show me your work so I can see where you're going wrong

Answer 12

alternatively, you can graph y = 3x^3 + 12x^2 + 3x - 18 in something like desmos

https://www.desmos.com/calculator

wherever you see the graph going through the x axis is an x-intercept (ie a root). There will be 3 roots for this equation.

Answer 13

Sorry, I had made a mistake in the calculation- I forgot to consider the exponent.

Answer 14

So I was correct originally, it is indeed 1? :)

@jim_thompson5910
Thanks so much for your help.

Is the answer 1?

Answer 15

yep, the only root in that list of answer choices is x = 1

the other roots are x = -3 and x = -2 (which aren't listed)