55=(3x-4)x

Solution for 55=(3x-4)x equation:

55=(3x-4)x

We move all terms to the left:

55-((3x-4)x)=0


We calculate terms in parentheses: -((3x-4)x), so:

(3x-4)x

We multiply parentheses

3x^2-4x

Back to the equation:

-(3x^2-4x)


We get rid of parentheses

-3x^2+4x+55=0

a = -3; b = 4; c = +55;
Δ = b2-4ac
Δ = 42-4·(-3)·55
Δ = 676
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{676}=26$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-26}{2*-3}=\frac{-30}{-6}
=+5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+26}{2*-3}=\frac{22}{-6}
=-3+2/3
$