Respuesta :

Answer:

(a+b) (a-b) =a^2 - b^2

In this question a=2, b=square root of 5

So 2*2=4 square root of 5 times square root of 5 is 5

4-5=-1

Answer:

I believe the answer is -1.

Step-by-step explanation:

So I distributed,

2 x 2 = 4

[tex]-\sqrt{5}[/tex] x 2 = [tex]-2\sqrt{5}[/tex]

[tex]\sqrt{5}[/tex] x 2 = [tex]2\sqrt{5}[/tex]

[tex]\sqrt{5}[/tex] x [tex]-\sqrt{5}[/tex] = -5

4 [tex]-2\sqrt{5}[/tex] + [tex]2\sqrt{5}[/tex] - 5 = ?

the radicals cancel out and 4 -5 = -1