what is the sum of the roots of the polynomial shown below? f(x)=3x^3+12x^2+3x-18

Question

campbell_st · Answer

well given the polynomial 

$$P(x) =ax^3 + bx^2 + cx + d$$

and if it has roots

$$\alpha, \beta, \gamma $$

then the sum of the roots is 

$$\alpha + \beta+ \gamma = \frac{-b}{a}$$

in your question a = 3 and b = 12

hope it helps

paxpolaris · Answer

$$f(x)=3\left( x^3+4x^2+x-6 \right)$$

f(1)=0
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paxpolaris · Answer

$$f(x)=\left( x-1 \right)\left( x^2+5x+6 \right)\ f(x)=(x-1)(x+2)(x+3)$$

1-2-3 = -4  .. same as campbell_st  ... answer verified