Explanation:
Given expressions:
1. x² + x
2. 5x² - 25x
3. x² - 16
4. x² + 4x + 4
5. x² - 5x + 6
Problem: Factor each of the quadratic expression
Solution:
A quadratic expression is an expression whose highest power is two.
1. x² + x
For this expression:
x² + x
Factorizing x since it is a common term;
x(x + 1)
2. 5x² - 25x
For this expression;
Factorize 5x since it common to both of them;
5x(x - 5)
3. x² - 16
For this expression;
Apply the differences of two squares;
x² - 16
x² - 4²;
Note; x² - y² = (x-y)(x+y)
So, x² - 4² = (x-4)(x + 4)
4. x² + 4x + 4
To solve this,
Find two numbers whose product will be 4 and sum also 4;
x² + 4x + 4 = x² + 2x + 2x + 4
= x(x + 2) + 2(x + 2)
= (x + 2)(x + 2)
5. x² - 5x + 6
To factorize this expression, simply find two numbers whose sum is -5 and product is 6;
x² - 5x + 6 = x² - 3x - 2x + 6
= x (x - 3) -2(x - 3)
= (x -2)(x-3)