Dr. J's Maths.com
Where the techniques of Maths
are explained in simple terms.

Algebra - Factorisation.
Summary of steps for the Cross-Method approach.


 

1. Write down the quadratic expression or equation.
2. Draw a large X under the expression.
3. Write x terms at the top and bottom on the left side of the X.
4. Write factors of the constant term at the top and bottom on the right side of the X.

Choose these factors (if there is a choice) with a thought to the coefficient of the x term.
Larger coefficients for the x term imply the factors should have greater difference.
5. Check the signs by reference to both the x term and the constant term.
6. Check the cross multiplication to see if you obtain the required middle term with correct sign.
7. Write down the factors you have developed.
8. Smile at obtaining the correct factorisation.