b)575- [(-6)x+70]=445
-6x+70=575-445=130
-6x=130-70=60
x= 60:(-6)
x=-10
Vậy x=-10
c)
315+(125-x)=435
125-x= 435-315= 120
x=125-120
x=5
Vậy x= 5
Các câu hỏi tương tự
Giai giup minh bai toan tinh nhanh nay nhe
a) 7/4+7/28+7/70+7/130
b) 99/98-98/97+1/97×98
c) 51×115+37×102-17×45-37×2
d) 10+1/90-1/72-1/56-1/42-1/30-1/20-1/6-1/2
A=1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72
Ai nhanh nhat minh se tik cho nha nhan len nhe
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90
cac ban giup mik voi
A= 1/2+5/6+11/12+19/20+29/30+41/42+55/56+71/72+89/90+109/110
GIUP MK NHA AI NHANH NHAT MK TICH CHO
bai 2 :xy,mn-0,xy=19,94
a ) 12,8 x 195 + 12,8 x 804 + 12,8
b) 1/2 +1/6 + 1/12+ 1/20+ 1/30 +1/42 +1/56 +1/72+ 1/90
tính
B= 1/6 +1/20+ 1/30 +1/42 +1/56 +1/72 +1/90
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72=????
Tính nhanh :
70/3 x ( 39/30 + 39/42 ) - 246/7 : ( 41/56 + 41/72 )
57/20 - 26/15 + 139/20 : 3
39/4 + 2/3 x ( 11 - 23/4 )
( 1 - 1/2 ) x ( 1 - 1/3) x ( 1 - 1/4 ) x ....( 1 - 1/2004 )
1/2+1/6+1/12+1/20+1/30+1/42+1/56+1/72 = ?