0=-4(4t^2-17t-15)

Solution for 0=-4(4t^2-17t-15) equation:

0=-4(4t^2-17t-15)

We move all terms to the left:

0-(-4(4t^2-17t-15))=0

We add all the numbers together, and all the variables

-(-4(4t^2-17t-15))=0


We calculate terms in parentheses: -(-4(4t^2-17t-15)), so:

-4(4t^2-17t-15)

We multiply parentheses

-16t^2+68t+60

Back to the equation:

-(-16t^2+68t+60)


We get rid of parentheses

16t^2-68t-60=0

a = 16; b = -68; c = -60;
Δ = b2-4ac
Δ = -682-4·16·(-60)
Δ = 8464
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{8464}=92$
$t_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-68)-92}{2*16}=\frac{-24}{32}
=-3/4
$
$t_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-68)+92}{2*16}=\frac{160}{32}
=5
$