Simplify: (t-5)² + 4(10-t)

First, expand the squared term: (t-5)² = (t-5)(t-5) = t² - 5t - 5t + 25 = t² - 10t + 25

Now, expand the second term: 4(10-t) = 40 - 4t

Now, put the two simplified terms together: t² - 10t + 25 + 40 - 4t

Combine like terms: t² - 14t + 65

So, the simplified expression is: t² - 14t + 65.