x .20/4+15.x-x/4x8=170 hỏi x=bn
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15 x 25 x 7 x 4 + 170 x 160
= (25 x 4) x (15 x 7) + 170 x 160
= 100 x 105 + 27200
= 10500 + 27200
= 37700
15 x 25 x 7 x 4 + 170 x 160
= ( 25 x 4 ) x ( 15 x 7 ) + 27200
= 100 x 105 + 27200
= 10500 + 27200
= 37700
Tk nha!!
a) \(15-3\left(x-1\right)-x=20\)
\(15-3x+3-x=20\)
\(-4x=2\)
\(x=-\frac{1}{2}\)
b) \(6x-2\left(x+3\right)=10\)
\(6x-2x-6=10\)
\(4x=16\)
\(x=4\)
c) \(25:\left(x+4\right)=5\)
\(x+4=25:5=5\)
\(x=1\)
d tự làm nha!
[ 19/20 x 3/4 + 1/20 x 3/4 ] x [ 1/2 x 3/4 -2/4 x 3/4 ]
=[ 3/4 x [19/20 + 1/20 ] x [3/4 x [2/4 - 1/2]
=[ 3/4 x 1 ] x [3/4 x 0 ]
=0
\(\left(\frac{19}{20}.\frac{3}{4}+\frac{1}{20}.\frac{3}{4}\right).\left(\frac{1}{2}.\frac{3}{4}-\frac{2}{4}.\frac{3}{4}\right)\)
\(=\left(\frac{19}{20}.\frac{3}{4}+\frac{1}{20}.\frac{3}{4}\right).\left(\frac{1}{2}.\frac{3}{4}-\frac{1}{2}.\frac{3}{4}\right)\)
\(=\left(\frac{19}{20}.\frac{3}{4}+\frac{1}{20}.\frac{3}{4}\right).0\)
\(=0\)
9/5 : 7/4 + 3/4 x 8/7
= (9/5 : 8/7) x (7/4 + 3/4)
= 63/40 x 5/2
= 63/16
7 x 3/14 - 1/14
= 3/2 - 1/4
= 5/4
\(\dfrac{9}{5}:\dfrac{7}{4}+\dfrac{3}{4}\times\dfrac{8}{7}\)
\(=\dfrac{9}{5}\times\dfrac{4}{7}+\dfrac{3}{4}\times\dfrac{8}{7}\)
\(=\dfrac{36}{35}+\dfrac{6}{7}\)
\(=\dfrac{66}{35}\)
\(7\times\dfrac{3}{14}-\dfrac{1}{14}\)
\(=\dfrac{3}{2}-\dfrac{1}{14}\)
\(=\dfrac{10}{7}\)
a) \(5x^3+6x^2+12x+8=0\)
\(\Leftrightarrow x^3+3.2.x^2+3.2^2.x+2^3+4x^3=0\)
\(\Leftrightarrow\left(x+2\right)^3=-4x^3\)
\(\Leftrightarrow x+2=-x\sqrt[3]{4}\)
\(\Leftrightarrow x\left(1+\sqrt[3]{4}\right)=-2\)\(\Leftrightarrow x=\frac{-2}{1+\sqrt[3]{4}}\)
b) ĐK: \(x\ge15\)
Đặt \(\sqrt[3]{x-20}=a\);\(\sqrt{x-15}=b\ge0\)
ta có: \(a^3-b^2=x-20-x+15=-5\)
\(\Rightarrow\hept{\begin{cases}a+b=7\\a^3+b^2=-5\end{cases}}\)
Giải hệ rùi thay vào thôi
(12x-4^3)x8^3=4x8^4
=> (12x-64)x512=16384
=> 12x-64=16384:512
=> 12x-64=32
=> 12x = 32+64
=> 12x = 96
=> x = 96:12
=> x = 8
a) (x - 7) + 5 = 16
=> x - 7 = 11
=> x = 18
b) 4 : x - 34 = 6
=> 4 : x = 40
=> x = \(\frac{1}{10}\)
c) 120 : ( x - 1 ) + 3 = 23
=> 120 : ( x - 1 ) = 20
=> x - 1 = 6
=> x = 7
d) 170 - ( x-7) : 5 = 20
=> ( x - 7 ) : 5 = 150
=> x - 7 = 750
=> x = 757
e) x + 12 + 2 .x + 3 = 4.x + 3
=> 3x + 17 = 4x + 3
=> x = 15
\(a,x-7=11\)
\(x=18\)
\(b,x-36=\frac{2}{3}\)
\(x=\frac{110}{3}\)
\(c,120:\left(x-1\right)=20\)
\(x-1=6\)
\(x=7\)
\(d,\left(x-7\right):5=150\)
\(x-7=10\)
\(x=17\)
\(d,x+12+2.x+3-4.x-3=0\)
\(x.\left(1+2-4\right)+3-3+12=0\)
\(x.\left(-1\right)+12=0\)
\(x.\left(-1\right)=-12\)
\(x=12\)
Tìm x biết
a) 350 - ( 3 . x ) : 75 = 170 - 69
350 - ( 3 . x ) : 75 = 101
( 3 . x ) : 75 = 350 - 101
( 3 . x ) : 75 = 249
3 . x = 249 . 75
3 . x = 18675
x = 18675 : 3
x = 6225
b) 3/4 + 1/4 : x = -3
1/4 : x = -3 - 3/4
1/4 : x = -15/4
x = 1/4 : -15/4
x = -1/15
c) 5,5x + 1 = 13/15
11/2x = 13/15 - 1
11/2x = -2/15
x = -2/15 : 11/2
x = -4/165
d) 3/7 - x = 1/4 - ( -3/5 )
3/7 - x = 1/4 +3/5
3/7 - x = 17/20
x = 3/7 - 17/20
x = -59/140
Tìm x biết :
a) 350 - ( 3 . x ) : 75 = 170 - 69
*Giải :
a) 350 - (3.x) : 75 = 170 -69
350 - ( 3.x) : 75 = 101
(3.x) : 75 = 350 - 101
( 3.x): 75 = 249
(3.x) = 249 .75
( 3. x ) = 18675
x = 18675 : 3
=> x = 6225
Vậy x = 6225 .
b) 3/4 + 1/4 : x = -3
*Giải :b) 3/4 + 1/4 : x = -3
1/4 : x = -3 -3/4
1/4 : x = -15/4
x =1/4 : ( -15/4 )
=> x = -1/15
Vậy x = -1/15 .
c)5,5x +1 = 13/15
*Giải : c) 5,5 x +1 = 13/15
11/2x = 13/15 -1
11/2x = -2/15
x = -2/15:11/2
=> x = -4/165
Vậy x = -4/165
d) 3/7 - x = 1/4 - ( -3/50)
*Giải : d) 3/7 - x = 1/4 - (-3/50)
3/7 - x = 1/4 + 3/5
3/7 - x = 17/20
x = 3/7 - 17/20
=> x = -59/140
Vậy x = -59/140
Chúc bn học tốt nha bạn
Lời giải:
$x\times \frac{20}{4}+15\times x-\frac{x}{4}\times 8=170$
$x\times 5+15\times x-x\times 2=170$
$x\times (5+15-2)=170$
$x\times 18=170$
$x=170:18=\frac{85}{9}$
à mik quên mik chỉ cần cách làm hoi chứ ra kq rùi =10