(9x+1)(8x+1)=0

Solution for (9x+1)(8x+1)=0 equation:

(9x+1)(8x+1)=0

We multiply parentheses ..

(+72x^2+9x+8x+1)=0

We get rid of parentheses

72x^2+9x+8x+1=0

We add all the numbers together, and all the variables

72x^2+17x+1=0

a = 72; b = 17; c = +1;
Δ = b2-4ac
Δ = 172-4·72·1
Δ = 1
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1}=1$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(17)-1}{2*72}=\frac{-18}{144}
=-1/8
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(17)+1}{2*72}=\frac{-16}{144}
=-1/9
$