222k views
5 votes
Let g()=³-12²+21+98 and its known that g(-2)=0. Find all roots of g().

1 Answer

2 votes

Final Answer:

The roots of the function g(x) = x³ - 12x² + 21x + 98 are x = -2, x = 7, and x = -8.

Step-by-step explanation:

Since we know that g(-2) = 0, this means that x = -2 is a root of the function. We can use this information to factor the polynomial:

g(x) = (x - (-2))(x² + ax + b)

Expanding the product, we get:

g(x) = x³ + (a + 2)x² + (-2a - 2b)x + 2b

Comparing this to the given form of g(x), we can equate the coefficients of like terms:

a + 2 = -12

-2a - 2b = 21

2b = 98

Solving for a and b, we get:

a = -14

b = 49

Substituting these values back into the factored form, we get:

g(x) = (x - (-2))(x² - 14x + 49)

Further factoring the quadratic, we get:

g(x) = (x + 2)(x - 7)

Therefore, the roots of the function g(x) are x = -2, x = 7, and x = -8.

User Anderson K
by
8.0k points