a+(3/4)a=21

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Solution for a+(3/4)a=21 equation:



a+(3/4)a=21
We move all terms to the left:
a+(3/4)a-(21)=0
Domain of the equation: 4)a!=0
a!=0/1
a!=0
a∈R
We add all the numbers together, and all the variables
a+(+3/4)a-21=0
We multiply parentheses
3a^2+a-21=0
a = 3; b = 1; c = -21;
Δ = b2-4ac
Δ = 12-4·3·(-21)
Δ = 253
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1)-\sqrt{253}}{2*3}=\frac{-1-\sqrt{253}}{6} $
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+\sqrt{253}}{2*3}=\frac{-1+\sqrt{253}}{6} $

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