1/3b+1/4b=-7

Solution for 1/3b+1/4b=-7 equation:

1/3b+1/4b=-7

We move all terms to the left:

1/3b+1/4b-(-7)=0


Domain of the equation: 3b!=0

b!=0/3

b!=0

b∈R



Domain of the equation: 4b!=0

b!=0/4

b!=0

b∈R


We add all the numbers together, and all the variables

1/3b+1/4b+7=0

We calculate fractions


4b/12b^2+3b/12b^2+7=0

We multiply all the terms by the denominator


4b+3b+7*12b^2=0

We add all the numbers together, and all the variables

7b+7*12b^2=0

Wy multiply elements

84b^2+7b=0

a = 84; b = 7; c = 0;
Δ = b2-4ac
Δ = 72-4·84·0
Δ = 49
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{49}=7$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(7)-7}{2*84}=\frac{-14}{168}
=-1/12
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+7}{2*84}=\frac{0}{168}
=0
$