[tex] \sqrt{x+-1}=4 =\ \textgreater \ x-1=+-16 =\ \textgreater \ \left \{ {{x=17} \atop {x=-15}} \right. [/tex]
[tex] \frac{ \frac{7+9+10+5+9}{5} * 3 +7 }{4} = 7,75[/tex]
A=[tex] \frac{cat1*cat2}{2} = \frac{4*7}{2}= 14 cm^{2} [/tex]
[tex] \frac{ \sqrt{3} }{2} * \sqrt{3} = \frac{3}{2} [/tex]