Всем привет, помогите чем сможете. x! / (x-5)! =18*(x-2)! / (x-6)!

x! *(x-6)! / (x-2)! *(x-5)!)=18x! *(x-5)! *(x-6) / (x! *(x-1)*(x-2)*(x-5)!)=18 (x-6) / (x-1)*(x-2)=18 (x-6)=18 (x^2-3x+2) 18x^2-55x+42=0D=3025-3024=1x1=(55-1) /36=3/2x2=(55+1) /36=14/9