(-77)-(-39)= what does this equal

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?

Drag the tiles to the boxes to form correct pairs. not all tiles will be used. match each set of vertices with the type of quadrilateral they form.

X2 + y 2 = 36 x + y = 6 solve the system of equations.