\(3x^2 = 48\) is an example of a quadratic equation that can be solved simply. If \((x + 1)(x + 2) = 0\), then \(x + 1 = 0\) or \(x + 2 = 0\), meaning \(x = -1\) or ...
Rewrite \(y = {x^2} - 6x + 11\) in the form \(y = {(x - b)^2} + c\). To get \(b\) (the number inside the bracket), halve the coefficient (number in front) of the second term in the original equation.