solutions for algerbra 2

Question

What are the solutions for x squared minus 4 =0

A. (0, -4)

B.(-4,2)

C. (-2,2)

D.(0,2)

Answer 1

x^2 – 4 = 0

 

Add 4 to both sides:

 

x^2 = 4

 

Take square root of both sides:

 

√(x^2) == |x| = 2

 

± x = 2

 

x = ± 2

 

Looks like C is the answer (although I don't like their notation; I'd prefer set notation:

{-2,2}).

Answer 2

x^2-4=0 means x^2=4

 

sq-rt(x^2)=sq-rt(4)

 

sq-rt(4)=2

 

but remember when you square a negative number it is then positive, so it's really

 

absolute value of sqrt(4)

 

which can be positive or negative 2,

 

answer is c