Answer:
1 unit to be added
Explanation:
we need to find what needs to added with the expression
to make perfect square trinomial
we use completing the square method
LEts take x^2 + 4x
In completing the square method, we take the coefficient of x and divide it by 2. then we square it
4 divide by 2 is 2
2^2 = 4
So to make perfect square we need 4 at the end.
In the given expression we have +3, so we add 1 to get 4

