Divide the polynomial 12x2+2x−9 by 4x−2 . Then express the polynomial as the product of the divisor and the quotient plus the remainder. (1 point) Responses 12x2+2x−9=(4x−2)(3x+2)−5 12 x squared plus 2 x minus 9 is equal to open paren 4 x minus 2 close paren times open paren 3 x plus 2 close paren minus 5 12x2+2x−9=(4x−2)(3x+2)+5 12 x squared plus 2 x minus 9 is equal to open paren 4 x minus 2 close paren times open paren 3 x plus 2 close paren plus 5 12x2+2x−9=(4x−2)(3x−1)−11 12 x squared plus 2 x minus 9 is equal to open paren 4 x minus 2 close paren times open paren 3 x minus 1 close paren minus 11 12x2+2x−9=(4x−2)(3x+2)−13

1 answer

To divide the polynomial \( 12x^2 + 2x - 9 \) by \( 4x - 2 \), we can use polynomial long division.

Step 1: Divide the first term of the dividend by the first term of the divisor.

The first term of the dividend \( 12x^2 \) divided by the first term of the divisor \( 4x \) gives:

\[ \frac{12x^2}{4x} = 3x \]

Step 2: Multiply the entire divisor by \( 3x \) and subtract from the dividend.

Now we multiply \( 3x \) by the divisor \( 4x - 2 \):

\[ 3x(4x - 2) = 12x^2 - 6x \]

Next, we subtract this from the original polynomial:

\[ (12x^2 + 2x - 9) - (12x^2 - 6x) = 2x + 6x - 9 = 8x - 9 \]

Step 3: Repeat the process with the new polynomial \( 8x - 9 \).

Now divide the first term \( 8x \) by \( 4x \):

\[ \frac{8x}{4x} = 2 \]

Now we multiply the entire divisor \( 4x - 2 \) by \( 2 \):

\[ 2(4x - 2) = 8x - 4 \]

Next, we subtract this from the polynomial we obtained, \( 8x - 9 \):

\[ (8x - 9) - (8x - 4) = -9 + 4 = -5 \]

At this point, we cannot divide further since the remainder \(-5\) has a lower degree than the divisor \(4x - 2\).

Conclusion:

Now we can express the result. The quotient is \(3x + 2\) and the remainder is \(-5\).

Thus, we have:

\[ 12x^2 + 2x - 9 = (4x - 2)(3x + 2) - 5 \]

So the correct response is:

12x² + 2x − 9 = (4x − 2)(3x + 2) − 5