completing the square of x^2-3x-8=0

Answer 1

x^2-3x-8=0

x^2 - 3x = 8
x^2 - 3x + 9/4 = 8 + 9/4
(x - 3/2)^2 = 41/4
x - 3/2 = ±√41/2

x = 3/2 ± √41/2 = (3 ±√41)/2

to find the term to be added to each side,
take 1/2 the coefficient of the x term , then square it
that is,
1/2 of 3 is 3/2, square it to get 9/4