7(k-1)(k+2)=0

Solution for 7(k-1)(k+2)=0 equation:

7(k-1)(k+2)=0

We multiply parentheses ..

7(+k^2+2k-1k-2)=0

We multiply parentheses

7k^2+14k-7k-14=0

We add all the numbers together, and all the variables

7k^2+7k-14=0

a = 7; b = 7; c = -14;
Δ = b2-4ac
Δ = 72-4·7·(-14)
Δ = 441
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$k_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$k_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{441}=21$
$k_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(7)-21}{2*7}=\frac{-28}{14}
=-2
$
$k_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+21}{2*7}=\frac{14}{14}
=1
$