Помогите решить примеры с решениями

293.
$\sqrt{a-b^2}= \sqrt{0.4-0.2^2}= \sqrt{0.4-0.04} = \sqrt{0.36}=0.6$
294.
$\sqrt{x+y^2} = \sqrt{0.4+0.3^2}= \sqrt{0.4+0.09}= \sqrt{0.49}=0.7$
295.
$\frac{1}{ \sqrt{1+x^2}}= \frac{1}{ \sqrt{1+ \frac{3}{4}^2}}= \frac{1}{ \sqrt{1+ \frac{9}{16} } } = \frac{1}{ \sqrt{ \frac{25}{16}} }= \frac{1}{1.25}=0.8$
296.
$\frac{y}{ \sqrt{1-y^2} } = \frac{ \frac{4}{5} }{ \sqrt{1- \frac{4}{5}^2} } = \frac{0.8}{ \sqrt{1- \frac{16}{25} } } \frac{0.8}{1-0.8} = \frac{0.8}{0.2}=4$
297.
$\frac{1}{ \sqrt{a}} - \sqrt{c} = \frac{1}{ \sqrt{0.04} } - \sqrt{0.64} = \frac{1}{0.2}-0.8=5-0.8=4.2$