[tex]a)\\\\2x^2+7=105 | -7\\2x^2=98|:2 \\x^2=49\\x=\sqrt{49}\\x=7\\\\\\b) \frac{14}{15x}=\frac{x}{105} \\15x*x=105*14 |:15\\x^2=7*14 \\ x^2=98 \\ x=\sqrt{49*2}\\x=7\sqrt{ 2}[/tex]
