-3=7(y-9/7)y=

Solution for -3=7(y-9/7)y= equation:

-3=7(y-9/7)y=

We move all terms to the left:

-3-(7(y-9/7)y)=0


Domain of the equation: 7)y)!=0

y!=0/1

y!=0

y∈R


We add all the numbers together, and all the variables

-(7(+y-9/7)y)-3=0

We multiply all the terms by the denominator


-(7(+y-9-3*7)y)=0


We calculate terms in parentheses: -(7(+y-9-3*7)y), so:

7(+y-9-3*7)y

We add all the numbers together, and all the variables

7(y-30)y

We multiply parentheses

7y^2-210y

Back to the equation:

-(7y^2-210y)


We get rid of parentheses

-7y^2+210y=0

a = -7; b = 210; c = 0;
Δ = b2-4ac
Δ = 2102-4·(-7)·0
Δ = 44100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{44100}=210$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(210)-210}{2*-7}=\frac{-420}{-14}
=+30
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(210)+210}{2*-7}=\frac{0}{-14}
=0
$