-3=7y(2y-7)

Solution for -3=7y(2y-7) equation:

-3=7y(2y-7)

We move all terms to the left:

-3-(7y(2y-7))=0


We calculate terms in parentheses: -(7y(2y-7)), so:

7y(2y-7)

We multiply parentheses

14y^2-49y

Back to the equation:

-(14y^2-49y)


We get rid of parentheses

-14y^2+49y-3=0

a = -14; b = 49; c = -3;
Δ = b2-4ac
Δ = 492-4·(-14)·(-3)
Δ = 2233
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(49)-\sqrt{2233}}{2*-14}=\frac{-49-\sqrt{2233}}{-28}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(49)+\sqrt{2233}}{2*-14}=\frac{-49+\sqrt{2233}}{-28}
$