a(4-a)=3.5

Solution for a(4-a)=3.5 equation:

a(4-a)=3.5

We move all terms to the left:

a(4-a)-(3.5)=0

We add all the numbers together, and all the variables

a(-1a+4)-(3.5)=0

We add all the numbers together, and all the variables

a(-1a+4)-3.5=0

We multiply parentheses

-1a^2+4a-3.5=0

a = -1; b = 4; c = -3.5;
Δ = b2-4ac
Δ = 42-4·(-1)·(-3.5)
Δ = 2
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{-(4)-\sqrt{2}}{2*-1}=\frac{-4-\sqrt{2}}{-2}
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+\sqrt{2}}{2*-1}=\frac{-4+\sqrt{2}}{-2}
$