Question

How to solve which number completes the square of the expression belo? 2x^2-3x+ 1. 9/8 2. 9 3. -9/2 4. 9/16

Answer 1

Answer:  1. $\dfrac{9}{8}$ .

Step-by-step explanation:

The given expression  $2x^2-3x+1$

Using completing the square method.

First, we divide the entire expression by 2 and write in the form of $x^2+bx=c$ , we get

$x^2-\dfrac{3}{2}x+\dfrac{1}{2}$

Such that $b=\dfrac{3}{2}\ \ \ , c=\dfrac{1}{2}$

Now add and subtract $(\dfrac{b}{2})^2$ on both sides.

$(\dfrac{b}{2})^2=(\dfrac{\dfrac{3}{2}}{2})^2\\\\=(\dfrac{3}{2\times2})^2\\\\=(\dfrac{3^2}{4^2})\\\\=\dfrac{9}{8}$

Here, we add and subtract $\dfrac{9}{8}$ .

Hence, the correct answer is  1. $\dfrac{9}{8}$ .