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What is the result when 12x3 + 20x2 + 11x + 2 is divided by 3x + 2?

1 Answer

5 votes

Answer: 3x + 2) 12x� + 20x� + 11x + 2

Divide the first term 12x� by 3x: %2812x%5E3%29%2F%283x%29=4x%5E2

and write 4x� above the 20x�:

4x�__________

3x + 2) 12x� + 20x� + 11x + 2

Multiply the 4x� by the (3x + 2) getting 4x%5E2%283x%2B2%29=12x%5E3%2B8x%5E2 and

write it under the first two terms and draw a line underneath:

4x�__________

3x + 2) 12x� + 20x� + 11x + 2

12x� + 8x�

Subtract %2812x%5E3%2B20x%5E2%29-%2812x%5E3%2B8x%5E2%29=12x%5E3%2B20x%5E2-12x%5E3-8x%5E2=12x%5E2,

and write 12x� under the line under 8x�, like this:

4x�__________

3x + 2) 12x� + 20x� + 11x + 2

12x� + 8x�

12x�

Now bring down the next term + llx and write in next to the 12x�

4x�__________

3x + 2) 12x� + 20x� + 11x + 2

12x� + 8x�

12x� + 11x

Divide the first term on the bottom 12x� by 3x: %2812x%5E2%29%2F%283x%29=4x

and write + 4x above the 11x at the top, like this:

4x� + 4x____

3x + 2) 12x� + 20x� + 11x + 2

12x� + 8x�

12x� + 11x

Multiply the 4x by the (3x + 2) getting 4x%283x%2B2%29=12x%5E2%2B8x and

write it under the first two terms and draw a line underneath:

4x� + 4x____

3x + 2) 12x� + 20x� + 11x + 2

12x� + 8x�

12x� + 11x

12x� + 8x

Subtract %2812x%5E2%2B11x%29-%2812x%5E2%2B8x%29=12x%5E2%2B11x-12x%5E2-8x=3x,

and write 3x under the line under 8x, like this:

4x� + 4x____

3x + 2) 12x� + 20x� + 11x + 2

12x� + 8x�

12x� + 11x

12x� + 8x

3x

Now bring down the last term + 2 and write in next to the 3x

4x� + 4x____

3x + 2) 12x� + 20x� + 11x + 2

12x� + 8x�

12x� + 11x

12x� + 8x

3x + 2

Divide the first term on the bottom 3x by the 3x at the left:

%283x%29%2F%283x%29=1 and write + 1 above the + 2 at the top,

like this:

4x� + 4x + 1

3x + 2) 12x� + 20x� + 11x + 2

12x� + 8x�

12x� + 11x

12x� + 8x

3x + 2

Multiply the + 1 by the (3x + 2) getting 1%283x%2B2%29=3x%2B2 and

write it under the two terms at the bottom and draw a line

underneath:

4x� + 4x + 1

3x + 2) 12x� + 20x� + 11x + 2

12x� + 8x�

12x� + 11x

12x� + 8x

3x + 2

3x + 2

Subtract %283x%2B2%29-%283x%2B2%29=3x-3x=0,

and write 0 under the line under 2, like this:

4x� + 4x + 1

3x + 2) 12x� + 20x� + 11x + 2

12x� + 8x�

12x� + 11x

12x� + 8x

3x + 2

3x + 2

0

Now you are done and the answer is 4x%5E2%2B4x%2B1 and

since the remainder is 0 you do not have to put it over

the divisor 3x+%2B+2 and add it on like you do when

the remainder is not 0.

Explanation:

User Tagore Smith
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