Complete the steps to solve the polynomial equation x3 – 21x = –20. According to the rational root theorem, which number is a potential root of the polynomial
–7

0

1

3

Respuesta :

x^3 - 21x = -20add 20 to both sidesx^3 - 21 x + 20 = 0Rational Root Theorem:Factors of P (constant) 20 = 1, 2, 4, 5, 10, 20-------------------------------      Factors of Q (leading Coefficient) = 1
Possible zeros (all + -) 1/1, 2/1, 4/1, 5/1, 10/1, 20/1
Of the choices given only the number 1 is a possible root.

Answer:

Option C

Step-by-step explanation:

We are given that an equation[tex]x^3-21x=-20[/tex]

We have to find the root of given polynomial equation by using rational root theorem.

[tex]x^3-12 x+20=0[/tex]

Factor of 1 is 1.

Factors of 20 are [tex]\pm 1,\pm 2,\pm 4,\pm 5,\pm 10,\pm 20[/tex]

The  roots of given polynomial is in the form

[tex]\pm \frac{2}{1},\pm \frac{4}{1},\pm\frac{5}{1},\pm \frac{10}{1},\pm \frac{20}{1}[/tex]

When we substitute x=1 then we get

[tex]1-21+20=0[/tex]

Therefore, 1 is a root of given polynomial.

Hence, option C is correct.