d+(1/3)d+100+1.25d-10=280

Solution for d+(1/3)d+100+1.25d-10=280 equation:

d+(1/3)d+100+1.25d-10=280

We move all terms to the left:

d+(1/3)d+100+1.25d-10-(280)=0


Domain of the equation: 3)d!=0

d!=0/1

d!=0

d∈R


We add all the numbers together, and all the variables

d+(+1/3)d+1.25d+100-10-280=0

We add all the numbers together, and all the variables

2.25d+(+1/3)d-190=0

We multiply parentheses

d^2+2.25d-190=0

a = 1; b = 2.25; c = -190;
Δ = b2-4ac
Δ = 2.252-4·1·(-190)
Δ = 765.0625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2.25)-\sqrt{765.0625}}{2*1}=\frac{-2.25-\sqrt{765.0625}}{2}
$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2.25)+\sqrt{765.0625}}{2*1}=\frac{-2.25+\sqrt{765.0625}}{2}
$