(1-7a)(1-9a)=0

Solution for (1-7a)(1-9a)=0 equation:

(1-7a)(1-9a)=0

We add all the numbers together, and all the variables

(-7a+1)(-9a+1)=0

We multiply parentheses ..

(+63a^2-7a-9a+1)=0

We get rid of parentheses

63a^2-7a-9a+1=0

We add all the numbers together, and all the variables

63a^2-16a+1=0

a = 63; b = -16; c = +1;
Δ = b2-4ac
Δ = -162-4·63·1
Δ = 4
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4}=2$
$a_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-16)-2}{2*63}=\frac{14}{126}
=1/9
$
$a_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-16)+2}{2*63}=\frac{18}{126}
=1/7
$