Increasing/decreasing sequences

The terms of an increasing sequence are getting larger and larger, so

u_{n + 1} > u_{n}

whereas a decreasing sequence is getting smaller and smaller, so

u_{n + 1} < u_{n}

If a sequence is increasing for all $n,$ we say it is an increasing sequence (similar for decreasing).

Show that the sequence
$u_{n} = n^{2} + 2 n - 10$
is an increasing sequence.
Determine whether the sequence defined by
$u_{n} = n^{2} - 10 n + 4$
is an increasing sequence, a decreasing sequence, or neither.