Réponse :
bonjour
remplace les lettres par les chiffres donnés
A =x+2y+5z
=-2/15+2×5/3+5×(-8/9)
= -2/15+10/3-40/9
=-6/45+150/45-200/45
= -56/45
B = x/y
= -2/15÷5/3
= -2/15×3/5
= -6/75
=-2/25
C= x+y/z-y
= -2/15+5/3÷(-8/9)-5/3
= -2/15+25/15÷(-8/9)-15/9
= 23/15÷(-23/9)
= 23/15×9/-23
= 207/-345
=-3/5
D = 1/(-2/15)-1/5/3+1/(-8/9)
=1×15/-2-1×3/5+1×9/-8
= 15/-2-3/5+9/-8
= -300/40-24/40-45/40
=-369/40
Explications étape par étape
Réponse :
Explications étape par étape
Bonjour
calculer :
A=x+2y+5z
A = -2/15 + 2 * 5/3 + 5 * (-8/9)
A = -2/15 + 10/3 - 40/9
A = -2/15 + 50/15 - 40/9
A = 48/15 - 40/9
A = 144/45 - 200/45
A = -56/45
B=x/y
B = (-2/15) / (5/3)
B = (-2/15) x 3/5
B = -2/5 x 3/15
B = -2/5 x 1/5
B = -2/25
C=x+y/z-y
C = (-2/15 + 5/3)/(-8/9 - 5/3)
C = (-2/15 + 25/15) / (-8/9 - 15/9)
C = 23/15 / (-23/9)
C = 23/15 x -9/23
C = 23/23 x -9/15
C = -3/5
D=1/x-1/y+1/z
D = 1/(-2/15) - 1/(5/3) + 1/(-8/9)
D = -15/2 - 3/5 - 9/8
D = -300/40 - 24/40 - 45/40
D = -369/40
Soit x=-2/15
y=5/3
z=-8/9