u=(-6/7)4

Solution for u=(-6/7)4 equation:

u=(-6/7)4

We move all terms to the left:

u-((-6/7)4)=0

We multiply all the terms by the denominator


u*7)4)-((-6=0

Wy multiply elements

7u^2-6=0

a = 7; b = 0; c = -6;
Δ = b2-4ac
Δ = 02-4·7·(-6)
Δ = 168
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{168}=\sqrt{4*42}=\sqrt{4}*\sqrt{42}=2\sqrt{42}$
$u_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-2\sqrt{42}}{2*7}=\frac{0-2\sqrt{42}}{14}
=-\frac{2\sqrt{42}}{14}
=-\frac{\sqrt{42}}{7}
$
$u_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+2\sqrt{42}}{2*7}=\frac{0+2\sqrt{42}}{14}
=\frac{2\sqrt{42}}{14}
=\frac{\sqrt{42}}{7}
$