Question

Multiply and simplify: (2-√7) (2+√7)

Answers:
-45
4-√7
-3
4-4√7

Answer 1

@E.ali :))

Answer 2

\[(a-b)(a+b) = a^{2} - b^{2} \]Its kind of a quick way to multiply something specific like this out. So basically a is 2 and b is sqrt(7). a^2 = 2^2 = 4. And b^2 =
\[\sqrt{7}*\sqrt{7}=\sqrt{49} = 7\]So this means that a^2 - b^2 =

4 - 7 = -3

Answer 3

Its C .

Answer 4

-3