calculer les expressions suivantes et donner le résultat sous forme de fraction irréductible. (mathématique) ssvvpp c'est trop dure sa fais des heures je galère
Question
ssvvpp c'est trop dure sa fais des heures je galère deçue
1) 5/7+(2/7-5)
2) 3/4+2×5+1/2
3)(3/2+2)(5+1/2)
4) 4/5×(5/4+1)-3/10
5) -5/7+-2/7×1/3
6) 8+21×2/3
7) 7/3-4/3÷2/5
8) 2/5+3/5+(1-1/10)
9) (1/9-3/5)(8/5+7/9)
merci à se qui me répondra svp j'ai a faire sa pour demain.
1 Réponse
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1. Réponse maudmarine
Bonjour,
1) 5/7+(2/7-5)
= 5/7 + [2/7 - (5 x 7) / (1 x 7)]
= 5/7 + (2/7 + 35/7)
= 5/7 + 35/7
= 42/7
= (7 x 6) / (7 x 1)
= 6
2) 3/4+2×5+1/2
= 3/4 + 10 + 1/2
= 3/4 + (10 x 4) / (1 x 4) + (1 x 2) / (2 x 2)
= 3/4 + 40/4 + 2/4
= 45/4
3)(3/2+2)(5+1/2)
= [3/2 + (2 x 2) / (1 x 2)] x [(5 x 2) / (1 x 2) + 1/2]
= (3/2 + 4/2) x (10/2 + 1/2)
= 7/2 x 11/12
= 77/4
4) 4/5×(5/4+1)-3/10
= 4/5 x [5/4 + (1 x 4) / (1 x 4)] - 3/10
= 4/5 x (5/4 + 4/4) - 3/10
= 4/5 x 9/4 - 3/10
= 36/20 - 3/10
= (2 x 18) / (2 x 10) - 3/10
= 18/10 - 3/10
= 15/10
= (5 x 3) / (5 x 2)
= 3/2.
5) -5/7+-2/7×1/3
= - 5/7 - 2/21
= (- 5 x 3) / (7 x 3) - 2/21
= - 15/21 - 2/21
= - 17/21
6) 8+21×2/3
= 8 + 42/3
= 8 + 14
= 22
7) 7/3-4/3÷2/5
= 7/3 - 4/3 x 5/2
= 7/3 - 20/6
= 7/3 - (2 x 10) / (2 x 3)
= 7/3 - 10/3
= - 3/3
= - 1
8) 2/5+3/5+(1-1/10)
= (2 x 2) / (5 x 2) + (3 x 2) / (5 x 2) + [(1 x 10) / (1 x 10) - 1/10]
= 4/10 + 6/10 + (10/10 - 1/10)
= 10/10 + 9/10
= 19/10.
9) (1/9-3/5)(8/5+7/9)
= [(1 x 5) / (9 x 5) - (3 x 9) / (5 x 9)] [(8 x 9) / (5 x 9) + (7 x 5) / (8 x 5)]
= (5/45 - 27/45) x (72/45 + 35/45)
= - 22/45 x 2 520/45
= - 55 440/2 0254
= (45 x - 1 232) / (45 x 45)
= - 1 232/45.