Answer by JKismyhusbandbae:
[tex]\mathrm{Remove\:parentheses}:\quad \left(-a\right)=-a\\=-\frac{5}{8}\cdot \:8+10\\\frac{5}{8}\cdot \:8=5\\=-5+10\\\mathrm{Add/Subtract\:the\:numbers:}\:-5+10=5\\=5[/tex]
(5/8)x+10 if x=-8
(5/8)(-8)+10=
(5/8)(8)(-1)+10=
(5)(1/8)(8)(-1)+10=
(5)(8/8)(-1)+10=
(5)(1)(-1)+10=
(-5)+10=
-5+10=
5