1.
[tex]12 + 6:\frac{2}{3} = 12+6\cdot\frac{3}{2} = 12+3\cdot3 = 12 + 9 = 21 \ \ \ \ Odp. \ A.\\\\\sqrt{9^{2}+12^{2}} = \sqrt{81+144} = \sqrt{225} = \sqrt{15^{2}} = 15 \ \ \ \ Odp. \ D.[/tex]
2.
k = 1/8
l = 1/3
m = 1/3
n = 2/3
Odp. A. liczba k