[tex]8)a + b + c = 23[/tex]
[tex]x = 9[/tex]
[tex]b)2013 - (53a + 53b + 53c + 10x)[/tex]
[tex] = 2013 - [53(a + b + c) + 10x][/tex]
[tex] = 2013 - (53 \times 23 + 10 \times 9)[/tex]
[tex] = 2013 - (1219 + 90)[/tex]
[tex] = 2013 - 1309[/tex]
[tex] = 704[/tex]