Question

Which of the following constants can be added to x2 - 3x to form a perfect square trinomial?

3/4
1 1/2
2 1/4

Answer 1

`2 (1)/(4)`

Step-by-step explanation

We want to find the constant that must be added to

`{x}^(2) - 3x`

to form a perfect square.

Comparing the given expression to

`a{x}^(2) + bx + c`

we have

a=1 , b=-3 , and c=0.

We need to add

`{( (b)/(2a) })^(2)`

We substitute the values to get,

`{( ( - 3)/(2(1)) })^(2) = (9)/(4)`

We change this to mix numbers to get,

`2 (1)/(4)`

The last choice is correct.