Verified Answer :

  • First, factor out the greatest common factor \(2\) from the expression, giving \(2(x^2 + x - 56)\).
  • Next, find two numbers that multiply to \(-56\) and add to \(1\), which are \(8\) and \(-7\).
  • Write the quadratic as a product of binomials: \((x + 8)(x - 7)\).
  • Combine the GCF with the binomials for the final result: \(\boxed{2(x+8)(x-7)}\).

Explanation

  1. Analyzing the expression

We are tasked with factoring the quadratic expression \(2x^2 + 2x - 112\). Factoring a quadratic expression involves breaking it down into a product of simpler polynomials, typically binomials. Our first objective is to identify any common factors present in all terms of the expression. Looking at the coefficients 2, 2, and -112, we can see that each term is divisible by 2.

  1. Factoring out the GCF

We begin by factoring out the greatest common factor (GCF), which is 2, from the entire expression:
\[2x^2 + 2x - 112 = 2(x^2 + x - 56).\]
This simplifies the problem to factoring the quadratic trinomial inside the parentheses, \(x^2 + x - 56\).

  1. Finding the factors of the trinomial

To factor the trinomial \(x^2 + x - 56\), we look for two numbers, \(m\) and \(n\), such that their product is the constant term (\(-56\)) and their sum is the coefficient of the linear term (\(1\)).
Testing factors of \(56\):

  • \(-1 \times 56 = -56\), \(-1 + 56 = 55\)
  • \(-2 \times 28 = -56\), \(-2 + 28 = 26\)
  • \(-4 \times 14 = -56\), \(-4 + 14 = 10\)
  • \(-7 \times 8 = -56\), \(-7 + 8 = 1\)

The numbers \(-7\) and \(8\) satisfy both conditions.

  1. Final factoring step

Now that we have found the two numbers, \(-7\) and \(8\), we can write the trinomial \(x^2 + x - 56\) as the product of two binomials:
\[x^2 + x - 56 = (x - 7)(x + 8).\]
Finally, including the GCF we factored out earlier, the fully factored form of the original expression is:
\[2(x - 7)(x + 8).\]

Examples

Factoring quadratic expressions is a fundamental skill in algebra with many real-world applications. For example, if you are designing a rectangular garden and know that the area can be represented by the expression \(2x^2 + 2x - 112\), factoring this expression helps you determine the dimensions (length and width) of the garden in terms of \(x\). By finding factors like \((x+8)\) and \((x-7)\), you can easily calculate how the area changes as you vary the value of \(x\), which is helpful in optimizing space or predicting material costs.