-16t2+30t+42=0

Solution for -16t2+30t+42=0 equation:

-16t^2+30t+42=0

a = -16; b = 30; c = +42;
Δ = b2-4ac
Δ = 302-4·(-16)·42
Δ = 3588
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{3588}=\sqrt{4*897}=\sqrt{4}*\sqrt{897}=2\sqrt{897}$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-2\sqrt{897}}{2*-16}=\frac{-30-2\sqrt{897}}{-32}
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+2\sqrt{897}}{2*-16}=\frac{-30+2\sqrt{897}}{-32}
$