-10x^2-16x+42=0

Solution for -10x^2-16x+42=0 equation:

-10x^2-16x+42=0

a = -10; b = -16; c = +42;
Δ = b2-4ac
Δ = -162-4·(-10)·42
Δ = 1936
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1936}=44$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-16)-44}{2*-10}=\frac{-28}{-20}
=1+2/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-16)+44}{2*-10}=\frac{60}{-20}
=-3
$