Question 62773
x^2 - 4x - 5 = 0

Here we need to find two numbers whose sum is -4 and whose product is -5.

Clearly the numbers are -5 and 1.

==> x^2 + x - 5x - 5 = 0 [splitting the middle term]

==> x(x+1) - 5(x+1) = 0  [taking out the common factor]

==> (x+1)(x-5) = 0

==> x + 1 = 0  or x - 5 = 0

==> x = -1  or x = 5


Good luck!!!