Réponse :
1) = 25 x 2 - 9 x 4 = 50 -36 = 14 19 - 5 + 8 = 22
2) 4 + 12/2 = 4 + 6 = 10 = 2 x 2 + 5 = 4 + 5 = 9
3) 11 x 8 - 12 x 5 = 88 - 60 = 28 10² - 3 x 50 = 100 - 150 = -50
4) 4 - 5/3 = 12/3 - 5/3 = 7/3 1/6 - 1/7 = 7/42 - 6/42 = 1/42
3+ 1/3 = 9/3 + 1/3 = 10/3 3 - 1/3 = 9/3 - 1/3 = 8/3
10/3 : 8/3 = 10/3 x 3/8 = 10/8 = 5/4
5) 500 x 3/100 = 1500/100 = 15 800 x 3/4 = 2400/4 = 600
6) 54 et 98 sont divisibles par 2 et par 1
7)27 = 4 x 6 + 3
8) 13/11 > 11/17 car 13/11 est >1 et 11/17 <1 3/4= 9/12 <11/12
36/28 = 9/7 car 36/28 c'est 9x4/7x4
9) oui car la somme de ses chiffres est un mulktiple de 9 : 7 + 8 + 6 + 6 = 27
10) A =3(a - b) - 5a + 2b = 3a -3b - 5a + 2b = -2a - b
B = -2a + 3b - 7(a + b) = -2a + 3b - 7a - 7b = - 9a - 4b
11) 3² 10 puissance 0 4 puissance 14 x 4 puissance -5 = 4 puissance 9
12) 2x + 3 = 0 => 2x = -3 => x = -3/2
5x -4 /6 = 1 => 5x - 4 = 6 => 5x = 6 + 4 => 5x = 10 => x = 10/5 =2
x- 5 = 3x - 1 => x - 3x = -1 + 5 => -2x = 4 => x = -4/2 = -2
13) A = x(x - 3) B = x[(x - 1) + 2(x + 2)]
Explications étape par étape
