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.
`(9)/(8)` .

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-(3)/(2)x+(1)/(2)`

Such that
`b=(3)/(2)\ \ \ , c=(1)/(2)`

Now add and subtract
`((b)/(2))^2` on both sides.

`((b)/(2))^2=(((3)/(2))/(2))^2\\\\=((3)/(2*2))^2\\\\=((3^2)/(4^2))\\\\=(9)/(8)`

Here, we add and subtract
`(9)/(8)` .

Hence, the correct answer is 1.
`(9)/(8)` .