`1.`
`a) 4,5 . (-4/9)`
`=9/2 . (-4/9)=-2`
`b) (-11/15): 1 1/10`
`=(-11/15): 11/10`
`=(-11/15). 10/11`
`=10/15=2/3`
`c) -7/11 : (-3,5)`
`=7/11: 7/2=7/11 . 2/7=2/11`
`d) -5/12 + 4/37 +17/12 -41/37`
`=(17/12 - 5/12) - (41/37 - 4/37)`
`= 1 -1 =0`
`2.`
`a) x +1/12=-3/8`
`x + 2/24= -9/24`
`x = -9/24 - 2/24`
`x = -11/24`
`b) x -2 = -5/9`
`x - 18/9=-5/9`
`x = -5/9 + 18/9 = 13/9`
`c) 2/3 . x +5/7=3/10`
`x :3/2 + 50/70=21/70`
`x :3/2=21/70 -50/70 =-29/70`
`x=-29/70 .3/2=-87/140`
`d) 3/4 .x -1/2= 3/7`
`x : 4/3 -7/14=6/14`
`x :4/3 =6/14 +7/14`
`x :4/3=13/14`
`x =13/14 . 4/3=26/21`
