Math Problem Statement

The are of a rectangle is 4x²-13x-3, if its length is (x-3) find is width

Solution

The area of a rectangle is given by the formula: Area=Length×Width.\text{Area} = \text{Length} \times \text{Width}.

Given:

  • Area = 4x213x34x^2 - 13x - 3
  • Length = x3x - 3

To find the width, we can rearrange the area formula to solve for the width: Width=AreaLength=4x213x3x3.\text{Width} = \frac{\text{Area}}{\text{Length}} = \frac{4x^2 - 13x - 3}{x - 3}.

To divide 4x213x34x^2 - 13x - 3 by x3x - 3, we'll use polynomial division.

  1. Polynomial Division:
    • Divide the first term of the numerator by the first term of the denominator: 4x2x=4x.\frac{4x^2}{x} = 4x.
    • Multiply x3x - 3 by 4x4x: 4x×(x3)=4x212x.4x \times (x - 3) = 4x^2 - 12x.
    • Subtract this product from the original polynomial: (4x213x3)(4x212x)=x3.(4x^2 - 13x - 3) - (4x^2 - 12x) = -x - 3.
    • Now, divide the new first term by the first term of the denominator: xx=1.\frac{-x}{x} = -1.
    • Multiply x3x - 3 by 1-1: 1×(x3)=x+3.-1 \times (x - 3) = -x + 3.
    • Subtract this from the previous result: (x3)(x+3)=6.(-x - 3) - (-x + 3) = -6.

The division shows that: 4x213x3=(x3)(4x+1).4x^2 - 13x - 3 = (x - 3)(4x + 1).

Therefore, the width of the rectangle is 4x+14x + 1.

Summary:

  • Width: 4x+14x + 1

Would you like more details or have any questions?

Related Questions:

  1. How do you factor a quadratic expression?
  2. What is the relationship between area, length, and width in a rectangle?
  3. How do you use synthetic division for polynomial division?
  4. Can all quadratic expressions be factored?
  5. What happens if the divisor is not a factor of the polynomial?

Tip: When dividing polynomials, always double-check by multiplying the quotient by the divisor to ensure it equals the original polynomial.

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Math Problem Analysis

Mathematical Concepts

Algebra
Polynomial Division
Factoring Quadratics

Formulas

Area of a Rectangle = Length × Width
Polynomial Division

Theorems

Factoring a Quadratic Expression

Suitable Grade Level

Grades 8-10