2x (3x-2)-3(x^2-4x)=3x(x-7)+2
(6x^2 - 4x - 3x^2 + 12x = 3x^2 - 21x + 2)
(3x^2 + 8x = 3x^2 - 21x + 2)
(29x = 2)
(x = 2/29)
a) x/3 + x/12 = 15/4
Умножим обе части на 12:
(4x + x = 45)
(5x = 45)
(x = 9)
б) rac{7x-4}{9} - rac{3x+3}{4} = rac{8-x}{6}
Умножим обе части на 36:
(4(7x-4) - 9(3x+3) = 6(8-x))
(28x - 16 - 27x - 27 = 48 - 6x)
(x - 43 = 48 - 6x)
(7x = 91)
(x = 13)