(4/7)*p=21

Solution for (4/7)*p=21 equation:

(4/7)*p=21

We move all terms to the left:

(4/7)*p-(21)=0


Domain of the equation: 7)*p!=0

p!=0/1

p!=0

p∈R


We add all the numbers together, and all the variables

(+4/7)*p-21=0

We multiply parentheses

4p^2-21=0

a = 4; b = 0; c = -21;
Δ = b2-4ac
Δ = 02-4·4·(-21)
Δ = 336
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$p_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$p_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{336}=\sqrt{16*21}=\sqrt{16}*\sqrt{21}=4\sqrt{21}$
$p_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-4\sqrt{21}}{2*4}=\frac{0-4\sqrt{21}}{8}
=-\frac{4\sqrt{21}}{8}
=-\frac{\sqrt{21}}{2}
$
$p_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+4\sqrt{21}}{2*4}=\frac{0+4\sqrt{21}}{8}
=\frac{4\sqrt{21}}{8}
=\frac{\sqrt{21}}{2}
$