Question

5z в квадрате -9z-2=0

Answer 1

5z²-9z-2=0
D=(-9)²-4*5*(-2)=81+40=121=11²
$z_{1}= \frac{-(-9)- \sqrt{121} }{2*5} = \frac{9-11}{10} = \frac{-2}{10} = -\frac{1}{5} =-0.2 \\ z_{2}= \frac{-(-9)+\sqrt{121} }{2*5} = \frac{9+11}{10} = \frac{20}{10} =2$