Найти корни трехчлена: 5x^+9x-2и4x^-2x-0,75

5x^2{?}+9x-2 и 4x^2{?}-2x-0,75
1.
$5x^2+9x-2 = 0 \\ x_{1,2} = \frac{-9 +- \sqrt{9^2 - 4*5*(-2)}}{2*5} = \frac{-9 +- \sqrt{81 + 40}}{10} = \frac{-9 +- \sqrt{121}}{10} = \frac{-9 +-11}{10}$
$x_1= \frac{2}{10} = \frac{1}{5} \\ x_2= \frac{-20}{10}= -2$

2.
$4x^2-2x-0,75 = 0 \\ x_{1,2} = \frac{2 +- \sqrt{4 - 4*4*(-0,75)} }{8} = \frac{2 +- \sqrt{4 +12} }{8} = \frac{2+- 4}{8}$
$x_1= \frac{6}{8}= \frac{3}{4} \\ x_2= \frac{-2}{8}= \frac{-1}{4}$