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Find and simplify an expression for the area of five rows of x squares with side lengths of x centimeters .

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?

If f(x)=3x+1 and f^-1=x-1/3, then f^-1(7)=