7+1/5b=3/20b

Solution for 7+1/5b=3/20b equation:

7+1/5b=3/20b

We move all terms to the left:

7+1/5b-(3/20b)=0


Domain of the equation: 5b!=0

b!=0/5

b!=0

b∈R



Domain of the equation: 20b)!=0

b!=0/1

b!=0

b∈R


We add all the numbers together, and all the variables

1/5b-(+3/20b)+7=0

We get rid of parentheses

1/5b-3/20b+7=0

We calculate fractions


20b/100b^2+(-15b)/100b^2+7=0

We multiply all the terms by the denominator


20b+(-15b)+7*100b^2=0

Wy multiply elements

700b^2+20b+(-15b)=0

We get rid of parentheses

700b^2+20b-15b=0

We add all the numbers together, and all the variables

700b^2+5b=0

a = 700; b = 5; c = 0;
Δ = b2-4ac
Δ = 52-4·700·0
Δ = 25
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{25}=5$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-5}{2*700}=\frac{-10}{1400}
=-1/140
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+5}{2*700}=\frac{0}{1400}
=0
$