28x2-25x-42=0

Solution for 28x2-25x-42=0 equation:

28x^2-25x-42=0

a = 28; b = -25; c = -42;
Δ = b2-4ac
Δ = -252-4·28·(-42)
Δ = 5329
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{5329}=73$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-25)-73}{2*28}=\frac{-48}{56}
=-6/7
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-25)+73}{2*28}=\frac{98}{56}
=1+3/4
$