Need
3. simplify the expression x^{2} -2x-3/x^{2} -3x-4÷x-3/2x

4. cos (a+b)= cosacosb-sinasinb, then cos (20+60) is what?

the answer is 80. Hope this helps

Step-by-step explanation:

18

step-by-step explanation:

draw the shape and you will see that f and k are actually at adjacent vertices (points of the hexagon that are neighboring).   so find the distance between (1,2) and (4,2).   that is easy since (1,2) and (4,2) is just a vertical distance to count, which is 3.   it is a regular polygon which means all sides are congruent.   you have 6 sides (hexa) so multiply 6 by 3 to receive 18.