Completing the Square

Completing the Square is another method that can be used to solve quadratic equations. It involves adding a constant to both sides of the equation in oder to get a squared expression on one side of the equation.

Example:

Find the roots of the equation: x² + 6x + 4 = 0, correct to 3 significant figures.

Solution:

x² + 6x + 4 = 0

x² + 6x = –4

x² + 6x + 3² = –4 + 3²

(x + 3)² = 5

(x + 3) = or (x + 3) = –

x = – 3 or x = – – 3

x = – 3 or x = – – 3

x = –0.764 or x = –5.24 (correct to 3 sig. fig.)

The following videos will explain in detail how to solve quadratic equations using completing the square method.

Custom Search