2c*7c=4

Solution for 2c*7c=4 equation:

2c*7c=4

We move all terms to the left:

2c*7c-(4)=0

Wy multiply elements

14c^2-4=0

a = 14; b = 0; c = -4;
Δ = b2-4ac
Δ = 02-4·14·(-4)
Δ = 224
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{224}=\sqrt{16*14}=\sqrt{16}*\sqrt{14}=4\sqrt{14}$
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{14}}{2*14}=\frac{0-4\sqrt{14}}{28}
=-\frac{4\sqrt{14}}{28}
=-\frac{\sqrt{14}}{7}
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{14}}{2*14}=\frac{0+4\sqrt{14}}{28}
=\frac{4\sqrt{14}}{28}
=\frac{\sqrt{14}}{7}
$