Question

Fill in the blank with a number to make the expression a perfect square. x^(2)-8x + ?

Answer 1

`{x}^(2) - 8x + \boxed{16} \\ = {x}^(2) - 2 * 4 * x + {4}^(2) \\ = {(x - 4)}^(2)`

So, 16 should be added to the expression to make it a complete square.

Formula used : (a-b)²=a²-2ab+b²