a) Solve the following equation by completing the square: x^(2)+ 6x + 1= 0. b) Solve the following equation by factorisation: x^(2) - 4x - 5 = 0 c) Solve the following quadratic inequality: x^(2) - 4x - 5 < 0 (hint use your answer to part b)
a) x^(2) + 6x + 1 = 0
(x + 3)^(2) - 8 = 0
x = - 3 + sqrt(8) or x = - 3 - sqrt(8)
b) (x-5)(x+1) = 0
x = -1 or 5
c) using answer to part b:
(x-5)(x+1) < 0
draw its graph then:
-1<x<5