21x2=x2-7x+6

Solution for 21x2=x2-7x+6 equation:

21x^2=x2-7x+6

We move all terms to the left:

21x^2-(x2-7x+6)=0

We add all the numbers together, and all the variables

21x^2-(+x^2-7x+6)=0

We get rid of parentheses

21x^2-x^2+7x-6=0

We add all the numbers together, and all the variables

20x^2+7x-6=0

a = 20; b = 7; c = -6;
Δ = b2-4ac
Δ = 72-4·20·(-6)
Δ = 529
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{529}=23$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(7)-23}{2*20}=\frac{-30}{40}
=-3/4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(7)+23}{2*20}=\frac{16}{40}
=2/5
$