Đáp án:a/ $$x = \frac{3}{{14}}$$
b/$$x = {2.3^2} = 18$$
Giải thích các bước giải:a/$$\frac{x}{7} + {\left( {\frac{{ - 3}}{7}} \right)^2} = \frac{2}{7}:\frac{4}{3} < = > \frac{x}{7} + {\frac{{( - 3)}}{{{7^2}}}^2} = \frac{2}{7}.\frac{3}{4} < = > \frac{x}{7} + \frac{9}{{7.7}} = \frac{3}{{7.2}} < = > \frac{{7.2.x}}{{7.7.2}} + \frac{{9.2}}{{7.7.2}} = \frac{{3.7}}{{7.7.2}} < = > 14x + 18 = 21 < = > x = \frac{3}{{14}}$$
b/ $${(x - {3^2})^3} = {({3^3})^2} < = > {(x - {3^2})^3} = {({3^2})^3} < = > x - {3^2} = {3^2} < = > x = {2.3^2} = 18$$
