Question

Difficulty: MediumFactoring Polynomials
Find the completely factored form of the given polynomial:
2x2+2x−402x^2 + 2x - 40

Assume all missing values in the blanks are positive integers.

Answer:The completely factored expression is 【2】(x + 【5】)(x - 【4】).

Answer

The missing values are 2, 5, and 4. The completely factored expression is 2(x + 5)(x - 4).
Factoring out the greatest common factor of 2 leaves x2+x−20x^2 + x - 20. This trinomial factors into (x+5)(x−4)(x + 5)(x - 4) because 5 and -4 multiply to give -20 and add to give 1. Thus, the complete factored form is 2(x+5)(x−4)2(x + 5)(x - 4), corresponding to the blank values 2, 5, and 4.

Step-by-Step Solution

1
Factor out the greatest common factor (GCF) from all the terms in the polynomial.
2(x2+x−20)2(x^2 + x - 20)
Identifying and extracting the GCF of 2 simplifies the remaining trinomial, making it easier to factor.
2
Factor the resulting quadratic trinomial x2+x−20x^2 + x - 20.
Find two numbers that multiply to -20 and add to 1 (the coefficient of x).
To factor a trinomial of the form x2+bx+cx^2 + bx + c, you must find two factors of cc that add up to bb.
3
Identify the two numbers that satisfy the conditions.
The numbers are 5 and -4.
5×(−4)=−205 \times (-4) = -20 and 5+(−4)=15 + (-4) = 1.
4
Write the complete factorization by combining the GCF and the factored binomials.
2(x+5)(x−4)2(x + 5)(x - 4)
This represents the original polynomial completely factored into its simplest terms.

Key Concept

Factoring Polynomials with a Greatest Common Factor
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