#6.    Condense: 

> assume(x, positive);
 

> assume(y, positive);
 

> `+`(`*`(5, `*`(log[10](x))), `*`(2, `*`(log[10](`+`(`*`(4, `*`(x)))))), `-`(log[10](`+`(`*`(8, `*`(`^`(x, 5)))))));
 

`+`(`/`(`*`(5, `*`(ln(x))), `*`(ln(10))), `/`(`*`(2, `*`(ln(`+`(`*`(4, `*`(x)))))), `*`(ln(10))), `-`(`/`(`*`(ln(`+`(`*`(8, `*`(`^`(x, 5)))))), `*`(ln(10))))) (2.6.1)
 

> simplify(`+`(`/`(`*`(5, `*`(ln(x))), `*`(ln(10))), `/`(`*`(2, `*`(ln(`+`(`*`(4, `*`(x)))))), `*`(ln(10))), `-`(`/`(`*`(ln(`+`(`*`(8, `*`(`^`(x, 5)))))), `*`(ln(10))))), ln);
 

`/`(`*`(`+`(`*`(2, `*`(ln(x))), ln(2))), `*`(`+`(ln(2), ln(5)))) (2.6.2)
 

> combine(`/`(`*`(`+`(`*`(2, `*`(ln(x))), ln(2))), `*`(`+`(ln(2), ln(5)))), ln);
 

`/`(`*`(ln(`+`(`*`(2, `*`(`^`(x, 2)))))), `*`(ln(10))) (2.6.3)
 

>
 

> `+`(`*`(`/`(1, 2), `*`(ln(`+`(x, y)))), `-`(`*`(2, `*`(ln(`*`(x, `*`(y)))))), `-`(ln(x)), ln(y));
 

`+`(`*`(`/`(1, 2), `*`(ln(`+`(x, y)))), `-`(`*`(2, `*`(ln(`*`(x, `*`(y)))))), `-`(ln(x)), ln(y)) (2.6.4)
 

> combine(`+`(`*`(`/`(1, 2), `*`(ln(`+`(x, y)))), `-`(`*`(2, `*`(ln(`*`(x, `*`(y)))))), `-`(ln(x)), ln(y)), ln);
 

ln(`/`(`*`(`^`(`+`(x, y), `/`(1, 2))), `*`(`^`(x, 3), `*`(y)))) (2.6.5)
 

> `+`(ln(`/`(`*`(`+`(x, `-`(1))), `*`(x))), ln(`/`(`*`(x), `*`(`+`(x, 1)))), `-`(ln(`+`(`*`(`^`(x, 2)), `-`(1)))));
 

`+`(ln(`/`(`*`(`+`(x, `-`(1))), `*`(x))), ln(`/`(`*`(x), `*`(`+`(x, 1)))), `-`(ln(`+`(`*`(`^`(x, 2)), `-`(1))))) (2.6.6)
 

> combine(`+`(ln(`/`(`*`(`+`(x, `-`(1))), `*`(x))), ln(`/`(`*`(x), `*`(`+`(x, 1)))), `-`(ln(`+`(`*`(`^`(x, 2)), `-`(1))))), ln);
 

`+`(`-`(ln(`+`(`*`(`^`(x, 2)), `-`(1)))), ln(`/`(`*`(`+`(x, `-`(1))), `*`(`+`(x, 1))))) (2.6.7)
 

> simplify(`+`(`-`(ln(`+`(`*`(`^`(x, 2)), `-`(1)))), ln(`/`(`*`(`+`(x, `-`(1))), `*`(`+`(x, 1))))));
 

`+`(`-`(`*`(2, `*`(ln(`+`(x, 1)))))) (2.6.8)