Question

giúp toi vs:>tks

Answer 1

\(1,\Delta=b^2-4ac=5^2-4.2=17>0\)

=> Pt có 2n pb

\(x_1=\dfrac{-b+\sqrt{\Delta}}{2a}=\dfrac{-5+\sqrt{17}}{4}\)

\(x_2=\dfrac{-b-\sqrt{\Delta}}{2a}=\dfrac{-5-\sqrt{17}}{4}\)

 

Answer 2

2,\(\Delta=b^2-4ac=\left(-1\right)^2-4.5.\left(-2\right)=41>0\)

=> Pt có 2n pb

\(x_1=\dfrac{-b+\sqrt{\Delta}}{2a}=\dfrac{1+\sqrt{41}}{10}\)

\(x_2=\dfrac{-b-\sqrt{\Delta}}{2a}=\dfrac{1-\sqrt{41}}{10}\)

Answer 3

3,\(\Delta=b^2-4ac=\left(-1\right)^2-4.9=-35< 0\)

=> Pt vô nghiệm

Answer 4