Question

Complete the square to make a perfect square trinomial. Write the result as a binomial square.

$a^2-20a$

Short answer

The result is$(a-10{)}^2$

Step-by-step solution

Given Information.   

The Given expression is $a^2-20a$.

Identify b, the coefficient of term having power one.   

$a^2-20a$

The coefficient of $a$ is $-20$.

So,$b=-20$

Find 12b2.

Substitute $b=-20$

$$\begin{gathered} ={\left(\frac{1}{2}(-20)\right)}^2 \\ ={\left(-10\right)}^2 \\ =100 \end{gathered}$$

Add 100to binomial expression to complete the square.  

$a^2-20a+100$

Rewrite as a binomial square.

$(a-10{)}^2$