bjr
ex 3
A = 3 x 5 + 7 x 8 - (-9 + 3) x 11
= 15 + 56 - (-6) x 11
= 71 + 66
= 137
B = (4/15) x 3 - (13/20) x 4 + 2
= 4/5 - 13/5 + 2 (on simplifie)
= -9/15 + 30/15
= 21/15
=7/5
C = (5/3) x (4/9) x (54/70) + 11/4
= (5 x 4 x 54)/(3 x 9 x 70) + 11/4 (on simplifie)
= 4/7 + 11/4
= 16/28 + 77/28
= 93/28
D = ( 2 + (4/5)x(10/3)) / (-7/3) + 5/2
= ( 2 + (8/3) ) / (-7/3) + 5/2
= ( (6/3) + (8/3) )/(-7/3) + 5/2
= (14/3)x(-3/7) + 5/2
= -2 + (5/2)
= (-4/2) + 5/2
= 1/2
