Question 152056
You are asked to find two numbers such that x and (-x) differ by 150.

So {{{x = -x + 150}}}
{{{2x = 150}}}
{{{x = 75}}}

To check, just sub in 75 in the original equation
{{{x = -x + 150}}} 
When x = 75 is this true?
{{{75 = -75 + 150}}}
{{{75 = 75}}} which is ture, so x =75 is correct