Answer:
Step-by-step explanation:
[tex]{\displaystyle \Delta =b^{2}-4ac} (for this equation b=-2 ; a=1 ; c=-4 )
Δ= (-2)^2-4*(-4)*1=4+16=20
\sqrt{20} =2\sqrt{5}
x_{1}=\frac{2+2\sqrt{5} }{2} = \frac{2(1+\sqrt{5)} }{2} =1+\sqrt{5
x_{2}=\frac{2-2\sqrt{5} }{2} = \frac{2(1-\sqrt{5)} }{2} =1-\sqrt{5 [/tex]
