7x*3x=24

Solution for 7x*3x=24 equation:

7x*3x=24

We move all terms to the left:

7x*3x-(24)=0

Wy multiply elements

21x^2-24=0

a = 21; b = 0; c = -24;
Δ = b2-4ac
Δ = 02-4·21·(-24)
Δ = 2016
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:

$\sqrt{\Delta}=\sqrt{2016}=\sqrt{144*14}=\sqrt{144}*\sqrt{14}=12\sqrt{14}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-12\sqrt{14}}{2*21}=\frac{0-12\sqrt{14}}{42}
=-\frac{12\sqrt{14}}{42}
=-\frac{2\sqrt{14}}{7}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+12\sqrt{14}}{2*21}=\frac{0+12\sqrt{14}}{42}
=\frac{12\sqrt{14}}{42}
=\frac{2\sqrt{14}}{7}
$