Question

Solve each of the quadratic equations below. Show your work.

x2 - 16 = 0

Answer 1

\[a^2 - b^2 = (a+b)(a-b)\] are you familiar with this?

Answer 2

^ To continue:

\(\Large \color{purple}{\rightarrow (x + 4)(x - 4) = 0 }\)

We can say, that either (x + 4) is 0, or (x - 4) is 0, as a number multiplied by 0 is 0.

So:

1) x + 4 = 0
x = -4

or

2) x - 4 = 0
x = 4

x can be either 4 or -4 with this.

Answer 3

How did I get four? \(\Large \color{purple}{\rightarrow a^2 = 16 }\)
\(\Large \color{purple}{\rightarrow a = \sqrt{16} = 4 }\)

Answer 4

\[X ^{2}-16=0\]
\[X ^{2}=16\]
\[X=\pm4\]