Factorising x³ + 13x² + 32x + 20
To factorise x³ + 13x² + 32x + 20, we need to follow a step-by-step process.
Step 1: Look for common factors
The first thing we should do is look for any common factors that we can factor out. In this case, we can factor out a common factor of 2:
x³ + 13x² + 32x + 20 = 2(x³/2 + 13x²/2 + 16x + 10)
Step 2: Factor the quadratic expression
Now that we have factored out the common factor of 2, we can focus on factoring the quadratic expression inside the parentheses. To do this, we need to find two numbers that multiply to 10 and add up to 16. These numbers are 2 and 8:
x³ + 13x² + 32x + 20 = 2(x + 2)(x² + 11x + 10)
Step 3: Factor the quadratic expression further
The quadratic expression x² + 11x + 10 can be factored into (x + 1)(x + 10):
x³ + 13x² + 32x + 20 = 2(x + 2)(x + 1)(x + 10)
Step 4: Check the factored expression
To check that our factorisation is correct, we can expand the expression using FOIL:
2(x + 2)(x + 1)(x + 10) = 2(x³ + 13x² + 32x + 20)
This confirms that our factorisation is correct.
Therefore, the fully factorised form of x³ + 13x² + 32x + 20 is 2(x + 2)(x + 1)(x + 10).