oblicz:
a)
[tex] \sqrt{7 \frac{9}{16} } \times \sqrt{5 } - {2}^{8} \div {2}^{6} [/tex]
b)

[tex] \sqrt{1 \frac{9}{16} } \times 4 + 1 \frac{2}{3} \div ( - \frac{2}{3} {)}^{3} [/tex]
​