[tex]5)\\-10y+18=-3(5y-7)+5y\ \ \ \ \ \ |omit\ bracket\\-10y+18=-15y+21+5y\ \ \ \ \ \ \ |unknowns\ on\ the\ left\\-10y+15y-5y=21-18\ \ \ \ \ \ \ \ \ |simplify \\0=3\\There\ is\ no\ solution.\\\\6)\\8(t+2)-3(t-4)=6(t-7)+8\\8t+16-3t+12=6t-42+8\\8t-3t-6t=-42+8-16-12\\-t=-62\\t=62[/tex]
[tex]7)\\4(5+2x)-5=3(3x+7)\\20+8x-5=9x+21\\8x-9x=21-20+5\\-x=6\\x=-6\\\\8)\\6(2x-8)+3=15\\12x-48+3=15\\12x=15+48-3\\12x=60\\x=5[/tex]