(3х² - 27)/(18 - 6х) = 3(х² - 9) / 6(3 - х) =
= (х - 3)(х + 3) / (-2)(х - 3) =
= -(х + 3)/2
18-х^2-4х-5х+20=-2
-х^2-4х-5х=-2-18-20
-х^2-9х=-40
1) (y+2)*(y-6)+(y+3)*(y-4)=4y-5
2)(z-3)*(3z+1)-(2z+3)*(4²-1)=6z+16
3) (2a-3B) *(7a +4B)-(3,5a+B) (4a-6B) =14,5a+6
4) =5n8