Si = (n-2)180º
2340 = 180n - 360 ---> 180n = 2340+360--> 180n = 1980---> n = 11 lados
D = [n(n-3)]/2
D = [11(11-3)]/2 ---> D = (11.8)/2 = 44 diagonais
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a)3(x-5) = 3x - 15
b) -(x-1)-2(x+5) = -x+1 - 2x - 10 = - 3x -9
c)10-3-2(x-3) = 10-3-2x+6 = 13 - 2x
d) -(x-3)-(x-2) = -x+3 -x + 2= -2x +5