Question

Calculati:
a) - 5/24- 7/36
b) - 0,14 + 3/20
c) -13/35 + ( - 1, 45 )

Answer 1

a)24=2³·3
   36=2²·3²
 ________
 c.m.m.m.c.=2³·3²=72
(-5·3)/72 - (7·2)/72 = (-15/72) - (14/72) = (-29/72)

b)-0,14= -14/100 = -7/50
   20=2²·5
   50=2·5²
 ________
 c.m.m.m.c.=2²·5²=100
(-7·2)/100 + (3·5)/100 = (-14/100) + 15/100 = 1/100 = 0,01

c)(-1,45)=(-145/100)=(-29/20)
   35=5·7
   20=2²·5
 ________
 c.m.m.m.c.=2²·5·7=140
(-13·4)/140 - (29·7)/140 = (-52/140) - 203/140 = (-255/140) = (-51/28)