Question

найдите нули функций y=x^2+6x-2 и y=49x^2 - 9


ПОЖАЛУЙСТА ОЧЕНЬ СРОЧНО ДАЮ 100 БАЛЛОВ

Answer 1

$1)\\\\y=x^{2} +6x-2\\\\y=0 \ \ \ \Rightarrow \ \ \ x^{2} +6x-2=0\\\\D=6^{2} -4\cdot (-2)=36+8=44=(2\sqrt{11} )^{2} \\\\\\x_{1}=\dfrac{-6-2\sqrt{11} }{2} =-3-\sqrt{11} \\\\\\x_{2}=\dfrac{-6+2\sqrt{11} }{2} =\sqrt{11} -3\\\\\\Otvet \ : \ -3-\sqrt{11} \ ; \ \sqrt{11} -3$

$\displaystyle\bf\\2)\\\\y=49x^{2} -9\\\\y=0 \ \ \ \Rightarrow \ \ \ 49x^{2} -9=0\\\\(7x-3)(7x+3)=0\\\\\\\left[\begin{array}{ccc}7x-3=0\\7x+3=0\end{array}\right\\\\\\\left[\begin{array}{ccc}7x=3\\7x=-3\end{array}\right\\\\\\\left[\begin{array}{ccc}x_{1} =\dfrac{3}{7} \\x_{2} =-\dfrac{3}{7} \end{array}\right \\\\\\Otvet \ : \ \frac{3}{7} \ ; \ -\frac{3}{7}$