![](https://rs.olm.vn/images/avt/0.png?1311)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
a, (1 999 + 2 378 + 4 545 + 7 956) – (315 + 598 + 736 + 89)
=1 999 + 2 378 + 4 545 + 7 956 – 315 - 598 - 736 - 89
= ( 1999 - 89 ) + ( 2 378 - 598 ) + ( 4 545 - 315 ) + ( 7 956 - 736 )
= ......0 + ........0 + .........0 + .......0
= ........0 có chữ số tận cùng là 0
![](https://rs.olm.vn/images/avt/0.png?1311)
71 x 25 + 71 x 19 + 44 x 29
= 71 x ( 25 + 19 ) + 44 x 29
= 71 x 44 + 44 x 29
= 44 x ( 71 + 29 )
= 44 x 100
= 4400
71x25+71x19+44x29
=71x(25+19)+44x29
=71x44+44x29
=44x(71+29)=44x100=4400
![](https://rs.olm.vn/images/avt/0.png?1311)
a) 35 x 2 x 9 x 5
= (35 x 9) x (2 x 5)
= (35 x 10 - 35) x 10
= (350 - 35) x 10
= 315 x 10 = 3150
b) 24 x 71 + 71 x 75 + 71
= 71 x (24+75+1)
=71 x 100
= 7100
![](https://rs.olm.vn/images/avt/0.png?1311)
=>6x + 1 + 2 + 3 + 4 + 5 + 6 + = 71
=>6x + 21 = 71
6x = 71 - 21 = 50
=>x = 50/6 = 25/3
(x+1)+(x+2)+(x+3)+(x+4)+(x+6)=71
=x*5+1+2+3+4+5+6=71
=x*5+21=71
=x*5=71-21
=x*5=50
=x=50:5
x=10
vậy x=10
![](https://rs.olm.vn/images/avt/0.png?1311)
a.11/7.8/13+8/13.3/7+8/13
=8/13.(11/7+3/7+1)
=8/13.3
=24/13
b.5/7.8/13+8/13.9/7-8/13
=8/13.(5/7+9/7-1)
=8/13.1
=8/13
c.157.199-56.199-199
=199.(157-56-1)
=199.100
19900
![](https://rs.olm.vn/images/avt/0.png?1311)
x+x+x+x*8+7= 71
4x *8+7= 71
4x *8 = 71-7
4x *8 = 64
4x = 64 : 8
4x = 8
x = 8 : 4
x = 2
Vậy x = 2.
tk mk đi mà !!!
x + x + x + x * 8 + 7 = 71
4x * 8 + 7 = 71
4x * 8 = 71 - 7
4x * 8 = 64
4x = 64 : 8
4x = 8
x = 8 : 4
x = 2