Question

HELP ITS AN EMERGENCY

Given the expression: 4x2 + 18x − 10


Part A: What is the greatest common factor? Explain how to find it. (3 points)


Part B: Factor the expression completely. Show all necessary steps. (5 points)


Part C: Check your factoring from Part B by multiplying. Show all necessary steps. (2 points)

Answer 1

Part A ----> 2

Part B ----> 2 (2x - 1) (x + 5)

Part C -----> See explanation below

Explanation:

Given expression is
4x² + 18x - 10

Part A

The greatest common factor (GCF) of the terms 4x², 18x and 10 is the largest number that divides into all three numbers without a remainder

To find this
Find the prime factors of each of the terms
4x² = 2 · 2 · x · x
18x = 2 · 3 · 3 · x
10 = 2 · 5

The prime factor common to all 3 is 2

Therefore the GCF of the expression is 2

Part B

The factored expression can be obtained by factoring out the GCF

4x² + 18x - 10 = 2(2x² + 9x - 5)

We can further factor the term in parentheses:
2x² + 9x - 5

To do this,

Break the expression into groups:

= (2x² - x) + (10x - 5)

Factor x from 2x² - x: x(2x - 1)

Factor 5 from 10x - 5: 5(2x - 1)

Therefore
(2x² - x) + (10x - 5) = x(2x - 1) + 5(2x - 1)

Factor out the common term 2x -1 to get
(2x - 1)(x + 5)

Therefore
4x² + 18x + 10 = 2 (2x - 1) (x + 5)

Part C
Checking if factorization is correct

Multiply (2x - 1)(x + 5) using the FOIL method
= 2x ·x + 2x · 5 + (-1) · x + (-1) · 5

= 2x² + 10x -1x -5

= 2x² + 9x - 5

Multiply the whole expression by 2
2 · 2x² + ² · 9x - 2 · 5

= 4x² + 18x + 10

which is the original expression

So the factorization is correct