(х-4)(х-5)-х(х-6)=10

x^2-5x-4x+20-(x^2+6x)=x^2-5x-4x+20-x^2-6x=-15x

( x - 4 )( x - 5 ) - x( x - 6 ) = 10 x^2 - 5x - 4x + 20 - x^2 + 6x = 10 - 9x + 20 + 6x = 10 - 3x = - 10 x = 10/3 x = 3 1/3