0=49x^2-28x-4

Solution for 0=49x^2-28x-4 equation:

0=49x^2-28x-4

We move all terms to the left:

0-(49x^2-28x-4)=0

We add all the numbers together, and all the variables

-(49x^2-28x-4)=0

We get rid of parentheses

-49x^2+28x+4=0

a = -49; b = 28; c = +4;
Δ = b2-4ac
Δ = 282-4·(-49)·4
Δ = 1568
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1568}=\sqrt{784*2}=\sqrt{784}*\sqrt{2}=28\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(28)-28\sqrt{2}}{2*-49}=\frac{-28-28\sqrt{2}}{-98}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(28)+28\sqrt{2}}{2*-49}=\frac{-28+28\sqrt{2}}{-98}
$