Biết: 14@3=45; 8@8=32; 25@5=80. Vậy 19@8=?
tìm x biết:
1) 14- (5-8+3-x) = |-7+10|
2) -19 - ?(3+x-5) = |4-15+2|
3) 45- (x+45-3) = |-7+3|
tìm x biết:
(82-5. x) : 13-4= 0
(32 . 45) :2=(x +70) :14 -40
45-[ ( 72-8.x): 4+7] . 3 = 0
(82 - 5.x) : 13 - 4 = 0
(82 - 5.x) : 13 = 0 + 4
(82 - 5.x) : 13 = 4
(82 - 5.x) = 4 . 13
(82 - 5.x) = 52
5.x = 82 - 52
5.x = 30
x = 30 : 5 = 6
(32 . 45) : 2 = (x + 70) : 14 - 40
720 = (x + 70) : 14 - 40
(x + 70) : 14 = 720 + 40
(x + 70) : 14 = 760
(x + 70) = 760 . 14
(x + 70) = 10640
x = 10640 - 70
x = 10570
Tìm x biết :
( 82 - 5 . x ) : 13 - 4 = 0
( 82 - 5 . x ) : 13 = 0 + 4
( 82 - 5 . x ) : 13 = 4
82 - 5 . x = 4 × 13
82 - 5 . x = 52
5 . x = 82 - 52
5 . x = 30
x = 30 : 5
x = 6
Vậy x = 6
a) ( 82- 5x ): 13- 4= 0
( 82- 5x ): 13 = 0+ 4
( 82- 5x ): 13 = 4
82- 5x = 4. 13
82- 5x = 52
5x = 82- 52
5x = 30
x = 30: 5
x = 6
b) ( 32. 45 ): 2= ( x+ 70 ): 14- 40
1440: 2 = ( x+ 70 ): 14- 40
720 = ( x+ 70): 14- 40
=> ( x+ 70 ): 14= 720+ 40
( x+ 70 ): 14 = 760
x+ 70 = 760. 14
x+ 70 = 10640
x = 10640- 70
x = 10570
Tìm x , biết :
a) 14-5+x=30
b) 45-(3+x)=14
c)18+(-3+x)-(44-x)=55
d) (x-45).27=0
e) 25.(42-x)=23
g) 156-(x+61)=82
h) 70-5(x-3)=45
i) | x+2 | = -(-8)+|-7|
k) (x-2)2 = 30-2.7
\(a,14-5+x=30\)
\(\Rightarrow9+x=30\Rightarrow x=30-9\)
\(\Rightarrow x=21\)
\(b,45-\left(3+x\right)=14\)
\(\Rightarrow3+x=45-14\)
\(\Rightarrow3+x=31\Rightarrow x=31-3\)
\(\Rightarrow x=28\)
\(c,18+\left(-3+x\right)-\left(44-x\right)=55\)
\(\Rightarrow18-3+x-44+x=55\)
\(\Rightarrow2x-29=55\Rightarrow2x=55+29\)
\(\Rightarrow2x=84\Rightarrow x=84:2\)
\(\Rightarrow x=42\)
\(d,\left(x-45\right).27=0\)
\(\Rightarrow x-45=0\Rightarrow x=45\)
\(a,14-5+x=30\)
\(\Rightarrow9+x=30\)
\(\Rightarrow x=30-9=21\)
\(b,45-\left(3+x\right)=14\)
\(\Rightarrow3+x=45-14=31\)
\(\Rightarrow x=31-3=28\)
Tìm y biết 35% của y la 14
Tính 70% của 45
Bài 6: Thực hiện phép tính
a)(-18)-(-3)-12
b)85.(35-27)-35.(85-27)
c)(-45).69+31.(-45)
Bài 7:Tìm x thuộc Z, biết:
a)(2-x)+10=-14
b)14.|x|=28
c)31-(17+x)=55
Bài 6:
a)\(\left(-18\right)-\left(-3\right)-12\)
\(=\left(-18\right)+3-12\)
\(=-15-12\)
\(=-27\)
b)\(85.\left(35-27\right)-35.\left(85-27\right)\)
\(=85.35-85.27-35.85+35.27\)
\(=85.\left(35-27-35\right)+35.27\)
\(=85.\left(-27\right)+35.27\)
\(=27.\left(-85+35\right)\)
\(=27.\left(-50\right)\)
\(=-1350\)
c)\(\left(-45\right).69+31.\left(-45\right)\)
\(=\left(-45\right).\left(69+31\right)\)
\(=\left(-45\right).100\)
\(=-4500\)
Bài 7:
a)\(\left(2-x\right)+10=-14\)
\(\Rightarrow2-x=-24\)
\(\Rightarrow x=26\)
b)\(14.\left|x\right|=28\)
\(\Rightarrow\left|x\right|=2\)
\(\Rightarrow\orbr{\begin{cases}x=2\\x=-2\end{cases}}\)
c)\(31-\left(17+x\right)=55\)
\(\Rightarrow17+x=-24\)
\(\Rightarrow x=-41\)
(-18)-(-3)-12=-27
85.(35-27)-35.(85-27)=-1350
(-45).69+31.(-45)=-4500
(2-x)+10=-14
\(\Leftrightarrow\)(2-x)=-14-10
\(\Leftrightarrow\)2-x=-24
\(\Rightarrow\)x=2-(-24)
\(\Rightarrow\)x=26
14.lxl=28
\(\Leftrightarrow\)lxl=28:14
\(\Leftrightarrow\)lxl=2
\(\Rightarrow\)x=-2
Tìm các số nguyên x biết: a) (-7).x = -35; b) ( -14) .x = -28 c) 22.x + 1= 45; d) ( -2) . x + 3 = -7
tìm x a,5+45(2x-1)=10 b, 54:(2 \(^{x-3}\)+1)+3=9 c, 14+36 :3\(^{x-5}\)=18
ai biết giúp micks với mick đang cần gấp cứu!!!!!!
a) 5 + 45(2x - 1) = 10
45(2x - 1) = 10 - 5
45(2x - 1) = 5
2x - 1 = 5 : 45
2x - 1 = 1/9
2x = 1/9 + 1
2x = 10/9
x = 10/9 : 2
x = 5/9
b) 54 : (2ˣ⁻³ + 1) + 3 = 9
54 : (2ˣ⁻³ + 1) = 9 - 3
54 : (2ˣ⁻³ + 1) = 6
2ˣ⁻³ + 1 = 54 : 6
2ˣ⁻³ + 1 = 9
2ˣ⁻³ = 9 - 1
2ˣ⁻³ = 8
2ˣ⁻³ = 2³
x - 3 = 3
x = 3 + 3
x = 6
c) 14 + 36 : 3ˣ⁻⁵ = 18
36 : 3ˣ⁻⁵ = 18 - 14
36 : 3ˣ⁻⁵ = 4
3ˣ⁻⁵ = 36 : 4
3ˣ⁻⁵ = 9
3ˣ⁻⁵ = 3²
x - 5 = 2
x = 2 + 5
x = 7
a: =>45(2x-1)=5
=>2x-1=1/9
=>2x=10/9
=>x=5/9
b: =>\(\dfrac{54}{2^{x-3}+1}=6\)
=>\(2^{x-3}+1=9\)
=>\(2^{x-3}=8\)
=>x-3=3
=>x=6
c: \(14+36:3^{x-5}=18\)
=>\(\dfrac{36}{3^{x-5}}=18-14=4\)
=>\(3^{x-5}=9\)
=>x-5=2
=>x=7
Tìm x biết:
a. x.7= -14
b, -5.x= 45