Question

What should be done to x^2 -8x to create a perfect square?

Answer 1

Step 1:

Write the expression

$x^2\text{ - 8x}$

Step 2:

$\begin{gathered} To\text{ make the expression a p}\operatorname{erf}ect\text{ square, find c from} \\ b^2\text{ = 4ac} \end{gathered}$

Step 3:

a = 1 , b = -8 , c = ?

Next, find c

$\begin{gathered} b^2\text{ = 4ac} \\ (-8)^2\text{ = 4 }\times\text{ 1 }\times\text{ c} \\ 64\text{ = 4c} \\ c\text{ = }\frac{64}{4} \\ c\text{ = 16} \end{gathered}$

Final answer

$\begin{gathered} To\text{ make } \\ x^2\text{ - 8x a p}\operatorname{erf}ect\text{ square , add 16} \\ x^2\text{ - 8x + 16} \end{gathered}$

Answer = 16