Question 32049This question is from textbook College Algebra
: I emailed you last night but was having computer problems, so thought I would try again. I am having problems decifering the difference between: solve by factoring, solve by completing the square, and solve by using the quadratic equation.
1) Using the quadratic equation x squared-4x-5=0, solve by factoring, solve by completing the square, and solve by using the quadratic formula.
Question 2) I don't know how different letters can replace other letters: For the function y=x squared-4x-5, put the function in the form y=a(x-h)squared+k. What is the line of symmetry? Graph the function using the equation in the first part. Explain why it is not necessary to plot points to graph when using y=a(x-h)squared+k.
Do you know where I can find the squared key and square root key?
This question is from textbook College Algebra
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! y=x^2-4x-5
Factoring: (x-5)(x+1)=0
x=5 or x=-1
Completing the square:
x^2-4x-5=0
(x^2-4x )=5
(x^2-4x+4)=5+4
(x-2)^2=9
Take the square root of both sides to get;
x-2=3 or x-2=-3
x=5 or x=-1
Quadratic Formula:
x^2-4x-5=0
a=1, b=-4, c=-5
x=[-b+-sqrt(b^2-4ac)]/2a
x=[4+-sqrt(16+20)]/2
x=[4+-sqrt(36)]/2
x=[4+-6]/2
x=(10/2)=5 or x=(4-6)/2=-1
Change of Form:
y=x^2-4x-5
y+5=x^2-4x
Complete the square to get:
x^2-4x+4=y+9
(x-2)^2=y+9
y=(x-2)^2-9
Axis of symmetry is x=2
For square rt type sqrt
For square use ^2
Cheers,
Stan H.
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