Question 389619
As long as you do the same thing to both sides
of the equation, it's OK
{{{-20 = -4x - 6x}}}
First multiply both sides by {{{-1}}}
{{{(-1)*(-20) = (-1)*(-4x) - (-1)*6x}}}
Now you simply have to know that 
(-)x(-) = (+)
{{{20 = 4x + 6x}}}
{{{x}}} is a common factor in {{{4x}}} and {{{6x}}}
so, you can express the right sides as 
{{{x*(4 + 6)}}}
{{{x*10}}}
Now the equation becomes
{{{20 = 10x}}}
Divide both sides by {{{10}}}
{{{x = 2}}}