Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(A=a+\left(42-70+18\right)-\left(42+18-a\right)\)
\(A=a+42-70+18-42-18-a\)
\(A=\left(a-a\right)+\left(42-42\right)+\left(18-18\right)-70\)
\(A=0+0+0-70=-70\)
( 2 x y + 2/15 ) x 3 = 4/5
( 2 x y + 2/15 ) = 4/5 : 3
( 2 x y + 2/15 ) = 4/15
2 x y = 4/15 - 2/15
2 x y = 2/15
y = 2/15 :2
y = 1/15
(2 x y + 2/15) x 3 = 4/5
2 x y + 2/15) = 4/5 : 3
2 x y + 2/15 = 4/15
2 x y = 4/15 - 2/15
2 x y = 2/15
y = 2/15 : 2
y = 1/15
7/9 x (2 - 1/3 x y) = 14/15
(2 - 1/3 x y) = 14/15 : 7/9
(2 - 1/3 x y) = 6/5
2 - y = 6/5 x 1/3
2 - y = 2/5
y = 2/5 + 2
y = 12/5
4/21 + 5 x y - 8/7 = 1/3
4/21 + 5 x y = 1/3 + 8/7
4/21 + 5 x y = 31/21
5 x y = 31/21 - 4/21
5 x y = 9/7
y = 9/7 : 5
y = 9/35
7/12 x y - 3/12 x y = 5
y x (7/12 - 3/12) = 5
y x 1/3 = 5
y = 5 : 1/3
y = 15
x - 36 : 18 = 12
=> x - 2 = 12
=> x = 14
vậy_
(x - 36) : 18 = 12
=> x - 36 = 216
=> x = 252
vậy_
b) x - 36 : 18 = 12
x - 2 = 12
x = 14
b) (x-36) : 18 = 12
x - 36 = 216
x = 252
x - 36 : 18 = 12
x - 2 = 12
x= 14
(x - 36) : 18 = 12
(x - 36) = 216
x = 216 + 36
x = 352
461 + (x - 45) = 387
461 + x - 45 = 387
x = 387 - 461 + 45
x = -29
(x-36):18=12
x-36=12x18
x-36=216
x=216+36
x= 252
x-36:18=12
x-2=12
x=14
461+(x-45)=387
x-45= 387 - 461
x-45=-74
x=-74+45
x=-29
a) A = a + (42-70+18) - (42+18+a)
= a + 42 - 70 + 18 - 42 - 18 - a
= (a-a) + (42-42) + (18-18) - 70
= 0 + 0 + 0 - 70 = -70.
Vậy A = -70.
b) B = a + 30 + 12 - (-20) + (-12) - (2+a)
= a + 30 + 12 + 20 - 12 - 2 - a
= (a-a) + (12-12) + (30+20-2)
= 0 + 0 + (50-2)
= 50 - 2 = 48.
Vậy B = 48.
c) C = (x-y+z) - (x-y-z) - (2x+y)
= x - y + z - x + y + z - 2x - y
= (x-x-2x) + (-y+y-y) + (z+z)
= -2x + (-y) + 2z
= -2x - y + 2z.
Vậy C = -2x - y + 2z.
\(y-36\times18=12\)
\(y-648=12\)
\(y=12+648\)
\(y=660\)
\(\left(y-36\right):18=12\)
\(y-36=12\times18\)
\(y-36=216\)
\(y=216+36\)
\(y=252\)