A student expanded an expression, as shown. Is the student's work correct? Explain why or why not.

Kelly is three years younger than her sister. the sum of their ages is 34 years. how old is kelly and how old is her sister?

The solution set for 5v2 – 125 = 0 is

Adrawer contains 12 identical white socks, 18 identical black socks and 14 identical brown socks. what is the least number of socks you must choose, without looking, to be certain that you have chosen two socks of the same colour?