Question

what number should be added x2- 4x toget a perfect square​

Answer 1

Answer:

2 is ur answer dear....................

Answer 2

Answer:

The answer is 4.

Explanation:

$x^{2}$ - 4x

The factor for this expression is

(x) (x) = $x^{2}$

The outer and Inner part must be added to get a total of - 4.

Then we can say that,

The last part will be (3)(1) or (1)(3) or (2)(2).

But out of the three it must be (2)(2) because we are completing a square.

(x-2) (x-2)

(x-2)2  (Using Multiplicative property)

Now if we foil the following (First, Inner, Outer, Last)  then we will get,

The First : (x) (x) = $x^{2}$

The outer part : (x) (-2) = -2x

The Inner part : (-2) (x) = -2x

The last Part : (-2) (-2) = 4

$x^{2}$ - 2x - 2x + 4

$x^{2}$ - 4x + 4

By splitting the middle term, we get the answer as 4.  

Hence, the answer is 4.