-14x^2=-21x

Solution for -14x^2=-21x equation:

-14x^2=-21x

We move all terms to the left:

-14x^2-(-21x)=0

We get rid of parentheses

-14x^2+21x=0

a = -14; b = 21; c = 0;
Δ = b2-4ac
Δ = 212-4·(-14)·0
Δ = 441
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{441}=21$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(21)-21}{2*-14}=\frac{-42}{-28}
=1+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(21)+21}{2*-14}=\frac{0}{-28}
=0
$