ex 1 :
a. (3x4/2x4) -7/8 = 12/8-7/8=18/8 simplifié 9x2/4x2= 9/4
b. (13x4/5x4) - (11x5/4x5) = (52-55) /20 = -3/20
c. -159/35
d.
ex 2 :
e. -2x7/7x5 = -14/35 = -7/5
f. 7/9x-5/5 = 7/9x-1=7/9
g. -7x((27+7)/3) = 7x34/3 = 238/3
h. (3+8) /12 x 4/3=11x4/12x3=44/36=11/9
i. 4/5x(-7/9)=4x-7/5x9=-28/45
j. 5-(24+35) /21= (105-59)/21 = 46/21
ex 3.
k. 18/15-11/15= 7/15
l. 8/15-7/2=(16-105)/30=-89/30
m. 3/2+24/10=(15+24)/10=39/10
