Question

Given f(x) = 3x2 + kæ - 1, and the remainder when f(x) is divided by x + 4 is27, then what is the value of k?

Answer 1

We will have that the value of k is the following:

Coefficients are: 3, k, & -1

And we will have x = -4

So:

-4 | 3 k -1

| -12 (-4k + 48)

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3 (k - 12) (-4k + 47)

Operation steps:

// -4(4) = -12

// k - 12

// -4(k -12) = -4k +48

//-1 +(-4k + 48) = -4k +47

So, we have that the remainder is -4k + 47, now we replace with the known value of the remainder: 27:

-4k + 47 = 27 => -4k = -20 => k = 5

So, the value of k is 5.