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
- 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.
- 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, \(x^2 + x - 56\).
- 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.
- 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.