Final answer:
To factorise the expression 8x^2 + 20, you can factor out the greatest common factor, which is 4. The x term has a coefficient of 0, so you can factor out 2x as well. The remaining expression inside the parentheses is 2x^2 + 5.
Step-by-step explanation:
To factorise the expression 8x^2 + 20, we need to find two numbers that multiply to give 20 and add up to give the coefficient of the x term, which is 0. In this case, the numbers are 2 and 10. Therefore, we can factorise the expression as 4(2x^2 + 5).