Réponse :
Explications étape par étape
Bonsoir
Soit x un nombre non nul. Calculer la valeur de x.
a. x/70 = 3/2
70x/70 = 3/2 * 70
x = 3 * 35
x = 105
b. 348/x = 4/5
348/x * x = 4/5 * x
348 = 4/5 * x
348 * 5/4 = 4/5 * x * 5/4
87 * 5 = x
x = 435
c. 5/6 = -4/x
5/6 * x = -4/x * x
5/6 * x = -4
5/6 * x * 6/5 = -4 * 6/5
x = -24/5
Recopier et completer.
a. 15/12 = 10/...?
15/12 = (3 x 5)/(3 x 4) = 5/4 = (5 x 2)/(4 x 2) = 10/8
15/12 = 10/8
b. 21/28 = .../32
21/28 = (7 x 3)/(7 x 4) = 3/4 = (3 x 8)/(4 x 8) = 24/32
21/28 = 24/32
c. -30/70 = .../42
-30/70 = (-3 x 10)/(7 x 10) = -3/7 = (-3 x 6)/(7 x 6) = -18/42
-30/70 = -18/42
d. 14/40 = 35/...
14/40 = (2 x 7)/(2 x 20) = 7/20 = (7 x 5)/(20 x 5) = 35/100
14/40 = 35/100
e. -18/16=.../24
-18/16 = (-2 x 9)/(2 x 8) = -9/8 = (-9 x 3)/(8 x 3) = -27/24
-18/16 = -27/24
f. 7/8 = .../100
7/8 = (7 x 12,5)/(8 x 12,5) = 87,5/100
