Question

Use the technique of completing the square to transform the quadratic equation into the form (x+c)2 = a.

x2 – 10x = 15

Answer 1

First add \((b \div 2)^2\) to both sides.

\( \color{Black}{\Rightarrow (-10 \div2)^2}\)

\( \color{Black}{\Rightarrow (-5)^2}\)

\( \color{Black}{\Rightarrow 25 }\)

So now the quadratic equation is in the form:

\( \color{Black}{\Rightarrow x^2 - 10x +25 = 40 }\)

Complete the square now.

\( \color{Black}{\Rightarrow (x - 5)^2 = 40 }\)

Answer 2

How though.

Answer 3

Erm? You always start by adding \((b \div 2)^2\) to both sides if the quadratic expression is not a perfect square.