-(1+7x)-6x(-7x)=36

Solution for -(1+7x)-6x(-7x)=36 equation:

-(1+7x)-6x(-7x)=36

We move all terms to the left:

-(1+7x)-6x(-7x)-(36)=0

We add all the numbers together, and all the variables

-(7x+1)-6x(-7x)-36=0

We multiply parentheses

42x^2-(7x+1)-36=0

We get rid of parentheses

42x^2-7x-1-36=0

We add all the numbers together, and all the variables

42x^2-7x-37=0

a = 42; b = -7; c = -37;
Δ = b2-4ac
Δ = -72-4·42·(-37)
Δ = 6265
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-7)-\sqrt{6265}}{2*42}=\frac{7-\sqrt{6265}}{84}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-7)+\sqrt{6265}}{2*42}=\frac{7+\sqrt{6265}}{84}
$