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)
1a) -54 . 76 + 12 .(-76) + 76.(-34)
= (-54 - 12 - 34).76
= -100 . 76
= -176
b) 37.(63 - 24) - 63.(24 + 37)
= 37 . 63 - 37 . 24 - 63.24 - 63 . 37
= (37.63 - 63.37) - (37 + 63) . 24
= 0 - 100 . 24
= - 2400
2a) x + (-27) = -23 - x
=> x + x = -23 + 27
=> 2x = 4
=> x = 4 : 2
=> x = 2
b) xy + 2x - y = 15
=> x(y + 2) - y = 15
=> x(y + 2) - (y + 2) = 13
=> (x - 1)(y + 2) = 13 = 1 . 13 = 13 . 1
Lập bảng :
x - 1 | 1 | -1 | 13 | -13 |
y + 2 | 13 | -13 | 1 | -1 |
x | 2 | 0 | 14 | -12 |
y | 11 | -15 | -1 | -3 |
Vậy ...
![](https://rs.olm.vn/images/avt/0.png?1311)
Bài 2:
a. $=62-81-12+59-9=(62-12)+(59-9)-81$
$=50+50-81=100-81=19$
b. $=39+13-26-62-39=(39-39)+13-(26+62)$
$=0+13-88=-(88-13)=-75$
c. $=(32-42)+(36-34)+(40-38)=10+2+2=14$
d. $=92-55+8-45=(92+8)-(55+45)=100-100=0$
Bài 1:
a. $=(387-87)-224=300-224=76$
b. $=-(75+35)+379=-110+379=379-110=269$
c. $=(11+15)-(13+17)=25-30=-5$
d. $=(31-21)-(27-24)=10-3=7$
![](https://rs.olm.vn/images/avt/0.png?1311)
a) \(-75+\left(-325\right)+\left|-45\right|-\left(-125\right)\)
\(=-75-325+45+125\)
\(=\left(45+125\right)-\left(75+325\right)\)
\(=170-400\)
\(=-230\)
b) \(62+\left|128\right|-\left|-155\right|-\left|70\right|\)
\(=62+128-155-70\)
\(\Leftrightarrow190-225\)
\(=-35\)
c) \(815+\left[95+\left(-815\right)+\left(-45\right)\right]\)
\(=815+95-815-45\)
\(=\left(815-815\right)+\left(95-45\right)\)
\(=0+50\)
\(=50\)
d) \(5+\left(-7\right)+9+\left(-11\right)+...+25+\left(-27\right)\)
\(=\left(5-7\right)+\left(9-11\right)+...+\left(25-27\right)\)
\(=-2-2-...-2\)
\(=-2.11\)
\(=-22\)
e) \(34+35+36+37-24-25-26-27\)
\(=\left(34-24\right)+\left(35-25\right)+\left(36-26\right)+\left(37-27\right)\)
\(=10+10+10+10\)
\(=40\)
![](https://rs.olm.vn/images/avt/0.png?1311)
b: =-24+76=52