x2 - 4 = 0

x = 2; x = -2
x = 2
no solutions
x = -2

Question

x2 - 4 = 0

x = 2; x = -2 
  x = 2 
  no solutions 
  x = -2

anonymous · Answer

Factor the left side of the equation as (x+2)(x-2).

If (x+2)(x-2)=0, then one or both of the factors must be equal 0.

Therefore, x must be -2 or 2.

anonymous · Answer

Lisa has three hog panels. Panel A is 8 feet long, panel B is 3 feet long, and panel C is 7 feet long. If the full length of each panel is used, can she build a triangular pen to hold her pet pig? No, 8 - 7 < 3 Yes, 3 + 7 > 8 No, 3 + 7 < 8 Yes, 8 - 3 > 7

anonymous · Answer

Why bother factoring? That is equivalent with $$x^2=4$$which immediately and apparently has solutions of $$x _{1,2}=\pm2$$