Answer :
Answer:
[tex]x=\dfrac{-(-1)\pm \sqrt{(-1)^{2}-4(7)(-9)}}{2(7)}[/tex]
Step-by-step explanation:
The quadratic equation is as follows :
[tex]7x^2=9+x[/tex] ...(1)
The solution of a quadratic equation [tex]ax^2+bx+c=0[/tex] is given by :
[tex]x=\dfrac{-b\pm \sqrt{b^2-4ac} }{2a}[/tex]
Equation (1) can also be written as follows :
[tex]7x^2-9-x=0\\\\7x^2-x-9=0[/tex]
Here, a = 7, b = -1 and c = -9
[tex]x=\dfrac{-b+ \sqrt{b^2-4ac} }{2a}, x=\dfrac{-b-\sqrt{b^2-4ac} }{2a}\\\\x=\dfrac{-(-1)+\sqrt{(-1)^{2}-4(7)(-9)}}{2(7)}, \dfrac{-(-1)-\sqrt{(-1)^{2}-4(7)(-9)}}{2(7)}\\\\x=1.20\ s, -1.06\ s[/tex]
Neglecting negative value.
So, it will hit the ground in 1.2 s.
Answer:
D
Step-by-step explanation:
Edge 2021 hope this helps :)