Question

Ex 14 pls dau coroana

Answer 1

$x=25\cdot[\sqrt{4\cdot0,(4)}+\sqrt{40\cdot0,0(4)}+\sqrt{400\cdot0,00(4)}]\\\\ x=25\cdot(\sqrt{4\cdot\frac{4}{9}}+\sqrt{40\cdot\frac{4}{90} }+\sqrt{400\cdot\frac{4}{900}})\\\\x=25\cdot(\sqrt{\frac{16}{9}}+\sqrt{\frac{160}{90}} +\sqrt{\frac{1600}{900}})\\\\x=25\cdot(\frac{\sqrt{16}}{\sqrt{9}}+\frac{\sqrt{160}}{\sqrt{90}}+\frac{\sqrt{1600}}{\sqrt{900}})\\\\x=25\cdot(\frac{4}{3} +\frac{4\sqrt{\not10} }{3\sqrt{\not10}}+\frac{4\not0}{3\not0} )\\\\x=25\cdot\frac{4+4+4}{3}$

$x=25\cdot\frac{12}{3}\\\\x=25\cdot4=100=10^2$