Bai 1: Tinh nhanh:
a, -69+53+46+(-14)+78 b, 13-12+11+10-9+8-7-6+5-4+3+2-1
Bai 2: a,Tim gia tri nho nhat cua bieu thuc: A= |x+19|+|y-5|+1890
b, Tim gia tri lon nhat cua bieu thuc: B= -|x-7|-|y+13|+1945
Bai 3: Tim x,y thuoc Z biet: a, xy-3x= -19 b, 3x+4y-xy= 16
Bai 4: Tim x thuoc Z biet: a, x.(x+3)= 0 b, (x-2) (5-x)= 0 c, (x+1) (x2+1)= 0
d, -12 (x-5)+7 (3-x)= 5 e, 30 (x+2)-6 (x-5)-24x= 100 f, (x+1)+(x+3)+(x+5)+. . .+(x+99)= 0
Minh xin cam on truoc ! THANK YOU
khó quá mình bó tay