Question

How do I graph f(x)=(x+3)(2x+1)

Answer 1

Step-by-step explanation:

First, since this is already in factored form, we can find the zeroes of this quadratic, which are -3 and -1/2. (To check, you can try plugging in these 2 values for x, and they indeed equal to zero.)

Now, we want to find the vertex. The x value would be exactly halfway between -3 and -1/2, which is -1.75. Now, we just need to evaluate it, so we can find the y value of the vertex:

(-1.75+3)(2*(-1.75)+1)

=(1.25)(-2.5)

=(-3.125)

Therefore, the vertex is at (-1.75, -3.125).

3 points define a parabola, so we can directly graph it now(graph attached to the answer).

I hope this helped.