(7a-2)(7a+2)=0

Solution for (7a-2)(7a+2)=0 equation:

(7a-2)(7a+2)=0

We use the square of the difference formula

49a^2-4=0

a = 49; b = 0; c = -4;
Δ = b2-4ac
Δ = 02-4·49·(-4)
Δ = 784
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{784}=28$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-28}{2*49}=\frac{-28}{98}
=-2/7
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+28}{2*49}=\frac{28}{98}
=2/7
$