Answer:
x = 4
x = - 4
Step-by-step explanation:
Method 1: Quadratic Formula
Ignore the A before the ±, it wouldn't let me type it correctly.
[tex]x=\frac{-b±\sqrt{b^{2} -4ac} }{2a}[/tex]
x² - 16 = 0
a = 1
b = 0
c = - 16
[tex]x=\frac{-(0)±\sqrt{0^{2} -4((1)(-16))} }{2(1)}[/tex]
[tex]x=\frac{0±\sqrt{0 -4((1)(-16))} }{2(1)}[/tex]
[tex]x=\frac{0±\sqrt{0 +64} }{2(1)}[/tex]
[tex]x=\frac{0±\sqrt{64} }{2}[/tex]
[tex]x=\frac{0±8 }{2}[/tex]
Two separate equations
One must have a + (positive) and the other will have a - (negative).
[tex]x=\frac{0+8 }{2}[/tex]
[tex]x=\frac{8 }{2}[/tex]
x = 8 ÷ 2
x = 4
[tex]x=\frac{-8 }{2}[/tex]
x = - 8 ÷ 2
x = - 4
Method 2: Factoring
x² - 16 = 0
(x - 4)(x + 4) = 0
Two separate equations
x - 4 = 0
x + 4 = 0
x - 4 = 0
x - 4 + 4 = 0 + 4
x = 4
x + 4 = 0
x + 4 - 4 = 0 - 4
x = - 4
