1) (4x+5) * 3=12х+15
2) (7x+3y+7) * (-4)=-28х-12у-28
3) 8 * (16a + 9b - 7) =128а+72b-56
4) 1/2(одна вторая) (18x + 20y + 16)=9х+10у+8
5) (a-b) - (b+a)=а-b-b-a=-2b
6) (x-y-z) + (y-x+z)=x-y-z+y-x+z=0
7) x-(x + y +z)=x-x-y-z=-y-z
8) xy-(xy + y + x)=xy-xy-y-x=-y-x
9) (14 - 5) - (6+10)=9-16=-7
10) (8x - 9y) - (8x - 9y) + 4=8x-9y-8x+9y+4=4