7p^2-52p+21=0

Solution for 7p^2-52p+21=0 equation:

7p^2-52p+21=0

a = 7; b = -52; c = +21;
Δ = b2-4ac
Δ = -522-4·7·21
Δ = 2116
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$p_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$p_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2116}=46$
$p_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-52)-46}{2*7}=\frac{6}{14}
=3/7
$
$p_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-52)+46}{2*7}=\frac{98}{14}
=7
$