Expanding the first product, the distribute property shows that  $$(u+4)(u-1) = u^2 + 4u - u - 4 = u^2 + 3u - 4.$$The second product becomes $$(u-3)(u+6) = u^2 - 3u + 6u - 18 = u^2 + 3u - 18.$$Subtracting, both the $u^2$ and the $3u$ terms cancel, leaving an answer of $-4 - (-18) = \boxed{14}$.
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Simplify $(u+4)(u-1) - (u-3)(u+6)$.
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
14
Simplify $(u+4)(u-1) - (u-3)(u+6)$.
test