a)
[tex] {2}^{2} + {a}^{2} = {5}^{2} \\ 4+ {a}^{2} = 25 \\ {a}^{2} = 21 \\ a = \sqrt{21} [/tex]
b)
[tex](2 \sqrt{5} ) ^{2} + ( \sqrt{5 } ) ^{2} = {b}^{2} \\ 4 \times 5 + 5 = {b}^{2} \\ 20 + 5 = {b}^{2} \\ {b}^{2} = 25 \\ b = \sqrt{25} = 5[/tex]
Myślę że pomogłem ;)
