Question

Find all x and y intercepts of the graph of the function f(x)= 2x^3+6x^2-2x-6

Answer 1

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Answer:

• y-intercept: (0, -6)
• x-intercepts: (-3, 0), (-1, 0), (1, 0)

Step-by-step explanation:

We notice the first pair of coefficients is the same as the last pair (with the sign changed). This means we can factor by grouping.

  f(x) = (2x^3 +6x^2) -(2x +6)

  f(x) = 2x^2(x +3) -2(x +3)

  f(x) = 2(x^2 -1)(x +3) = 2(x -1)(x +1)(x +3)

The factors are made to be zero when x is 1, -1, or -3.

The x-intercepts are (1, 0), (-1, 0), (-3, 0).

The y-intercept is the constant, -6.