Giải bài 7 trang 21 toán 7 tập 1 chân trời sáng tạo.

a) $\left ( \frac{2}{5} + \frac{1}{2}\right )^{2}$ = $\left ( \frac{4}{10} + \frac{5}{10}\right )^{2}$ =  $\left ( \frac{9}{10}\right )^{2}$ = $\frac{81}{100}$

b) $\left ( 0,75 + 1\frac{1}{2}\right )^{3}$ = $\left ( \frac{3}{4} + \frac{3}{2}\right )^{2}$ = $\left ( \frac{3}{4} + \frac{6}{4}\right )^{2}$ = $( \frac{9}{4} )^{2}$ = $\frac{81}{16}$

c) $\left ( \frac{3}{5} \right )^{15}$ : (0,36)= $\left ( \frac{3}{5} \right )^{15}$ : $\left ( \frac{3}{5} \right )^{10}$  = $\left ( \frac{3}{5} \right )^{5}$

d)  $\left ( 0,75 - 1\frac{1}{2}\right )^{3}$ = $\left ( \frac{3}{4} - \frac{3}{2}\right )^{3}$ = $\left ( \frac{3}{4} - \frac{6}{4}\right )^{3}$ = ($-\frac{3}{4}$)= $-\frac{27}{64}$