SOLUTION: 1) 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 quadra

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: 1) 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 quadra      Log On


   

Question 31919This question is from textbook college algebra
: 1) 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 algebra

Answer by mukhopadhyay(490) About Me  (Show Source):
You can put this solution on YOUR website!
x^2-4x-5=0
Using (a): x^2-5x+x-5=0
=>x(x-5)+1(x-5)=0
=>(x-5)(x+1)=0
=>x=5 or x=-1;
Using (b): x^2-4x-5=0
=>(x^2-4x)=5
=>[x^2-4x+(4/2)^2-(4/2)^2]=5
=>(x-2)^2=5+4
=>(x-2)^2=9
=>(x-2)=3 or (x-2)=-3
=>x=5 or x=-1;
Using (c): x^2-4x-5=0
The roots are [(-b)+/-sqrt(b^2-4ac)]/2a
a=1, b=-4, and c=-5
Substitute the value of a,b,and c to get the roots using quadratic formula