4.9x^2-17x-2.5=0

Solution for 4.9x^2-17x-2.5=0 equation:

4.9x^2-17x-2.5=0

a = 4.9; b = -17; c = -2.5;
Δ = b2-4ac
Δ = -172-4·4.9·(-2.5)
Δ = 338
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{338}=\sqrt{169*2}=\sqrt{169}*\sqrt{2}=13\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-17)-13\sqrt{2}}{2*4.9}=\frac{17-13\sqrt{2}}{9.8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-17)+13\sqrt{2}}{2*4.9}=\frac{17+13\sqrt{2}}{9.8}
$