SOLUTION: Using the quadratic equation x2 - 4x - 5 = 0, perform the following tasks: a) Solve by factoring. b) Solve by completing the square c) Solve by using the quadratic formula

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Using the quadratic equation x2 - 4x - 5 = 0, perform the following tasks: a) Solve by factoring. b) Solve by completing the square c) Solve by using the quadratic formula      Log On


   

Question 42871This question is from textbook College Algerbra
: Using the quadratic equation x2 - 4x - 5 = 0, perform the following tasks:
a) Solve by factoring.
b) Solve by completing the square
c) Solve by using the quadratic formula This question is from textbook College Algerbra

Answer by fractalier(6550) About Me  (Show Source):
You can put this solution on YOUR website!
a) From x^2 - 4x - 5 = 0, we have
(x - 5)(x + 1) = 0
x = 5 and x = -1
b) From x^2 - 4x - 5 = 0, we have
x^2 - 4x + 4 - 5 = 4
(x + 2)^2 - 5 = 4
(x + 2)^2 = 9
x + 2 = ± 3
x = 2 ± 3
x = 5, -1
c) From x^2 - 4x - 5 = 0, we have
x = (4 ± sqrt(16+20)) / 2
x = (4 ± sqrt(36)) / 2
x = (4 ± 6) / 2
x = 5, -1