This study notes covers Worked Example 1: Clean Numbers within Quadratic Formula for GCSE Mathematics. Revise Quadratic Formula in Algebra for GCSE Mathematics with 11 exam-style questions and 5 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 4 of 8 in this topic. Use this study notes to connect the idea to the wider topic before moving on to questions and flashcards.
Worked Example 1: Clean Numbers
Solve: x² + 5x + 6 = 0 using the quadratic formula
Step 1 Identify a, b, c
a = 1, b = 5, c = 6
Step 2 Calculate b² - 4ac
b² - 4ac = 5² - 4(1)(6)
= 25 - 24 = 1
Step 3 Apply the formula
x = (-5 ± √1) / 2(1)
x = (-5 ± 1) / 2
Step 4 Find both solutions
x = (-5 + 1) / 2 = -4/2 = -2
x = (-5 - 1) / 2 = -6/2 = -3
Practice questions for Quadratic Formula
For the equation 3x² − 5x + 2 = 0, what are the values of a, b, and c in the quadratic formula?
Explain what the value of the discriminant (b² − 4ac) tells you about the solutions to a quadratic equation.