Aidez moi maths niveau 3ème svp exercices 21+22

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numéro 21

a = 5 x + 7 - 24 - 15 x = - 10 x - 17

b = - 7 x + 3 + 18 - 9 x = - 16 x + 21

c = 3 + 18 x² - 16 x² + 20 = 2 x² + 23

d = - 8.2  - 4.1 x + 7.5 x + 0.5 x² = 0.5 x² + 3.4 x - 8.2

22
a = 8 x - 10 + 5 x + 7 - 24  - 15 x = - 2 x - 27

b = 9 x - 72 - x² +3 x - 7 x + 63 = - x² + 5 x - 9

c = - 3 - 12 x - 20 x - 32 + 4 x² - 7 x = 4 x² - 39 x - 35

d = 5 - 15 x² - 5 x - x² - 6 x + 4 x² = - 12 x² - 11 x  + 5