Question

if x +4 is factor of 3x³ +5x² +Kx+6 then find k​

Answer 1

If x + 4 is a factor of given polynomial then we will get zero after x = -4 in the given polynomial....

$3 {( - 4)}^{3} + 5 {( - 4)}^{2} + k( - 4) + 6 = 0 \\ \\ = > 3 \times ( - 64) + 5 \times 16 - 4k + 6 = 0 \\ \\ = > - 192 + 80 - 4k + 6 = 0 \\ \\ = > - 4k = 192 - 86 \\ \\ = > - 4k = 106 \\ \\ = > k = \frac{ - 106}{4} = \frac{ - 53}{2}$

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Answer 2

Answer:

when x+4 is factor of this equation.so x= -4.

so,3×(-4)(-4)(-4)+5×(-4)×(-4)+k×(-4)+6=0

-192+80-k4+6=0

-278-k4=0

-k4=278

-k =278/4

k= -69.5

Step-by-step explanation:

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