Bonjour, Résoudre les équations suivantes : 1) x/7=3/5 2) 7-4x=-5+2x 3) 3(4x-9)=-5(4-3x) 4) 3-(2x-7)= x+7

bonjour,

x/7 = 3/5 => x = 3/5x7 = 21/5

7 - 4x = -5x+2 => -4x +5x = 2-7 => x = -5

3(4x-9)=-5(4-3x) => 12x - 27 = -20 + 15x => -3x = 7 => x = -7/3

3-(2x-7)= x+7  -  pas sûr que l'énoncé soit correct

:)

Bonjour

1) x/7=3/5

X = 3/5*7 = 21/5

2) 7-4x=-5+2x

-4x-2x = 5-7

-6x = -2

X = -2/-6 = 1/3

3) 3(4x-9)=-5(4-3x)

12x -27 = -20 + 15 x

12x-15x = -20+27

-2x = 7

X = -7/2

4) 3-(2x-7)= x+7

3-2x+7 -x = 7

-3x = 7-10

-3x = -3

X = -3/-3

X= 1