Verified Answer :

  • Distribute each term of the first quadratic expression by the second quadratic expression: \((2x^2 - x + 4)(3x^2 + 5x - 7)\).
  • Perform individual multiplications: \(6x^4 + 10x^3 - 14x^2 - 3x^3 - 5x^2 + 7x + 12x^2 + 20x - 28\).
  • Simplify the expression by combining like terms for each power of \(x\).
  • The final expanded polynomial is \(\boxed{6x^4 + 7x^3 - 7x^2 + 27x - 28}\).

Explanation

  1. Understanding the Problem

To expand the product of the two quadratic expressions \((2x^2 - x + 4)\) and \((3x^2 + 5x - 7)\), we must distribute each term of the first expression by every term in the second expression. This process is based on the distributive property, which allows us to multiply a sum of terms by another sum of terms term-by-term. Our goal is to represent the final result as a single polynomial in the form \(ax^4 + bx^3 + cx^2 + dx + e\).

  1. Expanding the Product Terms

We expand the expression \((2x^2 - x + 4)(3x^2 + 5x - 7)\) by multiplying:
\[(2x^2)(3x^2 + 5x - 7) + (-x)(3x^2 + 5x - 7) + (4)(3x^2 + 5x - 7)\]
Distributing each term:

  1. First term: \(2x^2(3x^2) + 2x^2(5x) + 2x^2(-7) = 6x^4 + 10x^3 - 14x^2\)
  2. Second term: \(-x(3x^2) - x(5x) - x(-7) = -3x^3 - 5x^2 + 7x\)
  3. Third term: \(4(3x^2) + 4(5x) + 4(-7) = 12x^2 + 20x - 28\)
  1. Combining Like Terms and Final Result

Now, we group the terms with the same power of \(x\):

  • \(x^4\): \(6x^4\)
  • \(x^3\): \(10x^3 - 3x^3 = 7x^3\)
  • \(x^2\): \(-14x^2 - 5x^2 + 12x^2 = (-14 - 5 + 12)x^2 = -7x^2\)
  • \(x\): \(7x + 20x = 27x\)
  • Constants: \(-28\)

Combining these results, we get the final polynomial:
\(6x^4 + 7x^3 - 7x^2 + 27x - 28\).

Examples

Polynomial multiplication is fundamental in various fields, such as physics and engineering, where we analyze complex systems. For instance, when designing a bridge, engineers might need to calculate the area or volume of components whose dimensions are expressed as polynomials of a variable, such as the height or width of a support structure. By expanding these expressions, engineers can simplify calculations to determine the structural integrity and material requirements effectively.