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Given f(x)=3x³+3x+k, and the remainder when f(x) is divided by x+3x+3 is -74, then what is the value of k?

User Brybam
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1 Answer

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Final answer:

To find the value of k in the polynomial f(x) = 3x³ + 3x + k, divide it by x + 3x + 3 and find the remainder. Setting the remainder equal to -74, we solve the equation to get k = -47 - 21x.

Step-by-step explanation:

To find the value of k, we need to divide the polynomial f(x) = 3x³ + 3x + k by x + 3x + 3 and find the remainder. The remainder is given as -74. Let's use polynomial long division to find k:

Dividend: 3x³ + 3x + k
Divisor: x + 3x + 3

First, divide the first term of the dividend by the first term of the divisor which gives us 3x². Multiply x + 3x + 3 by 3x² and subtract the result from the dividend:

Dividend: 3x³ + 3x + k - (3x²(x + 3x + 3)) = 3x³ + 3x + k - (3x³ + 9x² + 9x) = -9x² - 6x + k

Now, divide -9x² by x + 3x + 3 which gives us -9x. Multiply x + 3x + 3 by -9x and subtract the result from the previous step:

-9x² - 6x + k - (-9x(x + 3x + 3)) = -9x² - 6x + k - (-9x² - 27x - 27) = 21x - 27 + k

Since this is the remainder and it is given as -74, we can set it equal to -74:

21x - 27 + k = -74

Now, solve for k:

21x - 27 = -74 - k
21x = -74 - k + 27
21x = -47 - k

The equation 21x = -47 - k means that the value of k is equal to -47 - 21x.

User Kimses
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