Question

tìm x

3x .(12x-4)-9x(4x -3) =30

x(5 -2x)+2x( x-1) =15 

Answer 1

a) 3x(12x - 4) - 9x(4x - 3) = 30

36x² - 12x - 36x² + 27x = 30

15x = 30

x = 2

b) x(5 - 2x) + 2x(x - 1) = 15

5x - 2x² + 2x² - 2x = 15

3x = 15

x = 5

Answer 2

a) 3x . (12x - 4) - 9x (4x - 3) = 30

=>  36x²  - 12x - 36x² + 27x = 30

=>  15x  = 30

=> x = 30  : 15 = 2

b) x (5 - 2x) + 2x (x - 1) = 15

  5x - 2x² + 2x² - 2x = 15

    3x = 15

=> x = 15 : 3 = 5