Question

What must be added to $x^2+2x$ to make it a perfect square?

• A. $\frac{1}{2}$
• B. 1
• C. 0.0
• D. 2

Answer 1

The correct option is B 1

Given expression is $x^2+2x$.

(Note that the coefficient of $x^2$ is 1. So, we need not convert this expression into standard form.)

So, in order to convert this expression into a perfect square, we need to add the square of half of the coefficient of x to it.

Here, the coefficient of x is 2.

Half of 2 is 1.

Square of 1 is 1.

Hence, we must add 1 to $x^2+2x$ to make it perfect square.