Question

What number should be added to the expression x2+2x to change it into a perfect square trinomial?

A)1
B)2
C)4
D)9

Answer 1

A is the correct answer. I just did gues and check so I don't know the correct method

Answer 2

Option A.
`1`

Explanation:

we know that

A perfect square trinomial is equal to

`(x+a)^(2)=x^(2)+2xa+a^(2)`

In this problem we have

`x^(2)+2x`

equate the equations and solve for a

`x^(2)+2x=x^(2)+2xa+a^(2)`

so

`2x=2xa`

`a=1`

therefore

the perfect square trinomial is equal to
`(x+1)^(2)`