y-7/8y=9

Solution for y-7/8y=9 equation:

y-7/8y=9

We move all terms to the left:

y-7/8y-(9)=0


Domain of the equation: 8y!=0

y!=0/8

y!=0

y∈R


We multiply all the terms by the denominator


y*8y-9*8y-7=0

Wy multiply elements

8y^2-72y-7=0

a = 8; b = -72; c = -7;
Δ = b2-4ac
Δ = -722-4·8·(-7)
Δ = 5408
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{5408}=\sqrt{2704*2}=\sqrt{2704}*\sqrt{2}=52\sqrt{2}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-72)-52\sqrt{2}}{2*8}=\frac{72-52\sqrt{2}}{16}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-72)+52\sqrt{2}}{2*8}=\frac{72+52\sqrt{2}}{16}
$