Question 34896
Go back to your sign properties ....
subtracting a negative is the same as adding a possitive.
{{{ -6-(-7)-15-(-12)= x }}}
{{{ -6+7-15+12 = x }}}
Now work left to right
{{{ 1-15+12 = x }}}
{{{ -14+12 = x }}}
{{{ -2 = x }}}