Question 112947
{{{-x+8+7x-(-1)}}} Start with the given expression



{{{-(-10)+8+7(-10)-(-1)}}} Plug in x=-10


{{{10+8+7(-10)+1}}} Negate the negatives. In other words, rewrite -(-10) as +10 and -(-1) as +1



{{{10+8-70+1}}} Multiply



{{{-51}}} Combine like terms



So {{{-x+8+7x-(-1)=-51}}} when x=-10