Respuesta :

Answer:

Solving the expression: [tex]\sqrt{(\sqrt{21}-2\sqrt{7} )^2}[/tex] we get [tex]\sqrt{21}-2\sqrt{7}[/tex]

Step-by-step explanation:

We need to solve the expression: [tex]\sqrt{(\sqrt{21}-2\sqrt{7} )^2}[/tex]

We know that [tex]\sqrt{x} = x^{\frac{1}{2}}[/tex]

Solving:

[tex]\sqrt{(\sqrt{21}-2\sqrt{7} )^2}\\=((\sqrt{21}-2\sqrt{7} )^2)^\frac{1}{2}[/tex]

We know that [tex](a^2)^\frac{1}{2}=a[/tex]

= [tex]\sqrt{21}-2\sqrt{7}[/tex]

So, solving the expression: [tex]\sqrt{(\sqrt{21}-2\sqrt{7} )^2}[/tex] we get [tex]\sqrt{21}-2\sqrt{7}[/tex]