(3x^3-17x^2+15x-25)/(x-5)

4 min read Jun 16, 2024
(3x^3-17x^2+15x-25)/(x-5)

Dividing Polynomials: (3x^3 - 17x^2 + 15x - 25) / (x - 5)

This article explores the division of the polynomial (3x^3 - 17x^2 + 15x - 25) by (x - 5) using polynomial long division.

Polynomial Long Division

Polynomial long division is a method used to divide polynomials. It is similar to the long division method used for dividing numbers.

Step 1: Set up the division.

Write the dividend (3x^3 - 17x^2 + 15x - 25) inside the division symbol and the divisor (x - 5) outside the division symbol.

             _________
x - 5 | 3x^3 - 17x^2 + 15x - 25 

Step 2: Divide the leading terms.

Divide the leading term of the dividend (3x^3) by the leading term of the divisor (x). This gives us 3x^2.

             3x^2      
x - 5 | 3x^3 - 17x^2 + 15x - 25 

Step 3: Multiply the divisor by the quotient.

Multiply the divisor (x - 5) by the quotient (3x^2) to get 3x^3 - 15x^2.

             3x^2      
x - 5 | 3x^3 - 17x^2 + 15x - 25 
       -(3x^3 - 15x^2) 

Step 4: Subtract.

Subtract the result from the dividend.

             3x^2      
x - 5 | 3x^3 - 17x^2 + 15x - 25 
       -(3x^3 - 15x^2) 
              -2x^2 + 15x 

Step 5: Bring down the next term.

Bring down the next term of the dividend (15x).

             3x^2      
x - 5 | 3x^3 - 17x^2 + 15x - 25 
       -(3x^3 - 15x^2) 
              -2x^2 + 15x - 25

Step 6: Repeat steps 2-5.

Divide the new leading term (-2x^2) by the leading term of the divisor (x). This gives us -2x. Multiply the divisor by the new quotient (-2x) and subtract. Bring down the next term (-25).

             3x^2 - 2x   
x - 5 | 3x^3 - 17x^2 + 15x - 25 
       -(3x^3 - 15x^2) 
              -2x^2 + 15x - 25
              -(-2x^2 + 10x)
                    5x - 25

Step 7: Repeat steps 2-5 again.

Divide the new leading term (5x) by the leading term of the divisor (x). This gives us 5. Multiply the divisor by the new quotient (5) and subtract.

             3x^2 - 2x + 5
x - 5 | 3x^3 - 17x^2 + 15x - 25 
       -(3x^3 - 15x^2) 
              -2x^2 + 15x - 25
              -(-2x^2 + 10x)
                    5x - 25
                    -(5x - 25)
                         0 

Result:

The quotient is 3x^2 - 2x + 5 and the remainder is 0. Therefore:

(3x^3 - 17x^2 + 15x - 25) / (x - 5) = 3x^2 - 2x + 5

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