(c+.75)(c-6)=0

Solution for (c+.75)(c-6)=0 equation:

(c+.75)(c-6)=0

We add all the numbers together, and all the variables

(c+0.75)(c-6)=0

We multiply parentheses ..

(+c^2-6c+0.75c-4.5)=0

We get rid of parentheses

c^2-6c+0.75c-4.5=0

We add all the numbers together, and all the variables

c^2-5.25c-4.5=0

a = 1; b = -5.25; c = -4.5;
Δ = b2-4ac
Δ = -5.252-4·1·(-4.5)
Δ = 45.5625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-5.25)-\sqrt{45.5625}}{2*1}=\frac{5.25-\sqrt{45.5625}}{2}
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-5.25)+\sqrt{45.5625}}{2*1}=\frac{5.25+\sqrt{45.5625}}{2}
$