4C - Solving quadratic equations
Learning intentions:
In this section we will examine:
- The null factor law and its use in solving simple quadric equations
Solving quadratic equations
The null factor law
The null factor law states:
Using the null factor law to solve quadratic equations
The null factor law can be used to solve simple quadratic equations. To solve quadratic equations, use the following steps:
- Get the quadratic equation to equal zero; that is, ax2 + bx + c = 0.
- Factorise the quadratic expression.
- Use the null factor law to find the solution
4C - VIDEO EXAMPLE 1:
Solve the following equation for x:
Note: The discriminant
(Δ) can be used to determine the number of expected solutions.
4C - VIDEO EXAMPLE 2:
Solve the following equation for x:
4C - VIDEO EXAMPLE 3:
Solve the following equation for x:
Success criteria:
You will be successful if you can:
- Apply the null factor law to factorised expressions to solve basic quadratic equations.