Question

How to solve which number completes the square of the expression below? 2x^2-3x+

1. 9/8
2. 9
3. -9/2
4. 9/16

Answer 1

see below

Explanation:

2x^2-3x+

Factor out 2

2( x^2 -3/2x)

Take the coefficient of x

-3/2

Divide by 2

-3/4

Square it

(-3/4) ^2 = 9/16

This is the number inside the square

2( x^2 -3/2x + 9/16)

Multiply by 2 since that is factored on the outside

9/16 *2 = 9/8

Add to the equation

2x^2-3x+9/8