23 треугольника,,...........................................................
3*(3/4+1/12-5/6)=
1) 3/4+1/12= 3*1/4*12=1*1/4*4=1/8
2) 1/8-5/6=1*5/8*6=5/48=9 3/48
3) 9 3/48*3=435/48*3=435*1/16=27 2/16=27 1/8
80 000х < 240 000 при
х=1, 80 000•1=80 000 < 240 000
х=2, 80 000•2=160 000 < 240 000
х= -1, 80 000•(-1)= -80 000 < 240 000
= 2 9/49 + 3 40/49 + 7 3/85 = 6 + 7 3/85 = 13 3/85;