bonjour,
A=-4/9 x -63/20
A= -4/9 x (-7x9)/(4x5)
A= (-4 x(-7x9)/9x(4x5)
A= -4x-7x9/9x4x5
A=-7/5
B=-14/25:7/10
B: -14/25 x 10/7
B= (-2x7)/(5x5) x (2x5)/7
B=-2x7x2x5/5x5x7
B=-4/5
C=(3/7-3):14/9
C= (3/7-(3x7)/7)x 9/14
C= (3-21)/7 x 9/14
C= -18/7 x 9/14
C= -18 x 9/ 7x14
C=-2x9x9/7x2x7
C= 9x9/7x7
C=81/49
D=6/5-2/7 x 21/8-19/20
D=6/5 -(2/7 x21/18)-19/20
D=6/5 -(2x21/7x18)-19/20
D=6/5-(2x3x7/7x2x3x3)-19/20
D=6/5-1/3-19/20
6/5=6x12/5x12=72/60
1/3=1x20/3x20=20/60
19/20=19x3/20x3=57/60
D=72/60-20/60-57/60
D=-5/60
D=-5x1/5x12=-1/12
E=2/7-5/2:35/4
E=2/7-5/2x4/35
E=2/7-(5/2x4/35)
E=2/7-(5x4/2x35)
E=2/7-(5x2x2/2x5x7)
E=2/7-2/7
E=0
G=(3+1/3):(1+4/5)
G=((3x3/3)+1/3): (1x5/5+4/5)
G=(9/3+1/3):(5/5+4/5)
G=10/3:9/5
G=10/3 x 5/9
G: 10x5/3x9
G=50/27
