№301
а) (2y+z)-(z-2y) = 2y+z-z+2y=2y
б) (x+3)-(5x-7) = x+3-5x+7=10-4x
в) (2a-1)+(3-4a) = 2a-1+3-4a=2-2a
г) (a+b)-(a-b)-(b-a) = a+b-a+b-b+a=a+b
д) 3m-(2m-3)+(2-m) = 3m-2m+3+2-m=5
е) (3y-1)-(2y-2)+(y-3) = 3y-1-2y+2+y-3=2y-2
№302
a) 2(a+b)+3(a+b)+2a = 2a+2b+3a+3b+2a=7a+5b
б) 5(x-z)-2(x+z) = 5x-5z-2x-2z=3x-7z
в) 2(2r-3s)-3(r-2s) = 4r-6s-3r+6s=r
г) 6(2a+c)+2(6a-c)-4c = 12a+6c+12a-2c-4c=24a
д) 3(x-1)+(x-2)-x = 3x-3+x-2-x=3x-5
е) 5n-3(n+2)+(n-6) = 5n-3n-6+n-6=3n-12
ж) m-(2m-6)+3(m-3) = m-2m+6+3m-9=2m-3
з) 2(3x+1)-(x-2)-3x = 6x+2-x+2-3x=2x+4