đkxđ x khác 6

(x+2).360/x-6=360

360x + 720 =360x - 2160

360x -360x = -2160 -720

x = -2880

mình đang cần gấp lên các bạn giải hộ mình

cái trên là cái 360 trên x cơ mà 360/x

Chọn C

C

C

Phép nhân

Ta có: 360 x (18 – 12) =  360 x 18 – 360 x 12

\(12\left(x+5\right)+2x=130\\\Leftrightarrow 12x+60+2x=130\\ \Leftrightarrow14x=70\\ \Leftrightarrow x=5\\ ----\\ 23\left(x-5\right)-12x=138\\ \Leftrightarrow23x-115-12x=138\\ \Leftrightarrow23x-12x=138+115\\ \Leftrightarrow11x=253\\ \Leftrightarrow x=\dfrac{253}{11}=23\\ ----\\ 360-12x+23\left(x-5\right)=278\\ \Leftrightarrow360-12x+23x-115=278\\ \Leftrightarrow-12x+23x=278+115-360\\ \Leftrightarrow11x=33\\ \Leftrightarrow x=\dfrac{33}{11}=3\)

\(6\left(x+3\right)+3\left(x-5\right)=278\\ \Leftrightarrow6x+18-3x-15=278\\ \Leftrightarrow6x-3x=278+15-18\\ \Leftrightarrow3x=275\\ \Leftrightarrow x=\dfrac{275}{3}\\ ---\\ \left(7-x\right)\left(3x-90\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}7-x=0\\3x-90=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=7\\x=30\end{matrix}\right.\)

\(\left(x-2\right)\left(4x-2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x-2=0\\4x-2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\4x=2\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=2\\x=\dfrac{1}{2}\end{matrix}\right.\\ ---\\ \left(2x-18\right)\left(3x-9\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}2x-18=0\\3x-9=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=18\\3x=9\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=9\\x=3\end{matrix}\right.\)

?????????????????

a) 32 : {160 : [360 - (175 + 21 x 5 )]} =32 : {160 : [360 - 280 ]}

                                                     =32 : {160 : 80}

                                                     =32 : 2= 16

b) (20 x 24 + 12 x 24 - 48 x 2 mũ 2) : 2 mũ 6 =(20 x 24 + 12 x 24 - 48 x 4) : 64

                                                                 = (480 + 288 - 192 ) : 64

                                                                 =576 : 64 = 9

đấy xong rồi

a)32:{160:[360-(175+21x5)]}

=32:{160:[360-(175+105)]}

=32:{160:80}

=32:2

=16

\(\left(x+2\right)\left(\dfrac{360}{x}-6\right)=360\)

\(ĐK:x\ne0\)

\(\Leftrightarrow\left(x+2\right)\left(\dfrac{360-6x}{x}\right)=360\)

\(\Leftrightarrow360-6x+\dfrac{720-12x}{x}=360\)

\(\Leftrightarrow360x-6x^2+720-12x=360x\)

\(\Leftrightarrow6x^2+12x-720=0\)

\(\Delta=12^2-4.6.\left(-720\right)\)

    \(=17424>0\)

`->` pt có 2 nghiệm

\(\left\{{}\begin{matrix}x_1=\dfrac{-12-\sqrt{17424}}{12}=-12\\x_2=\dfrac{-12+\sqrt{17424}}{12}=10\end{matrix}\right.\) ( tm )

Vậy \(S=\left\{-12;10\right\}\)

a) \(56-\left(x+31\right)=12\)

\(\Rightarrow x+31=44\)

\(\Rightarrow x=13\)

b) \(\left(2x+5\right)\cdot4=6^2\)

\(\Rightarrow2x+5=9\)

\(\Rightarrow2x=4\)

\(\Rightarrow x=2\)

a) 56 - ( x+31) = 12

\(\Rightarrow\) -x + 25 = 12

\(\Rightarrow\) -x = -13

\(\Rightarrow\) x = 13

b) ( 2x +5 ) . 4=6²

\(\Leftrightarrow\) (2x + 5) . 4 = 36

\(\Rightarrow\) 2x + 5 = 9

\(\Rightarrow\) 2x = 4

\(\Rightarrow\) x = 2

ĐKXĐ: \(x\ne0\)

Ta có: \(\left(x-6\right)\left(\dfrac{360}{x}+2\right)=360\)

=> \(360+2x-\dfrac{2160}{x}-12=360\)

<=> \(\dfrac{2x^2-12x-2160}{x}=0\)

=> \(x^2-6x-1080=0\)

<=> \(\left(x^2+30x\right)-\left(36x+1080\right)=0\)

<=> \(\left(x+30\right)\left(x-36\right)=0\)

<=> \(\left[{}\begin{matrix}x=-30\\x=36\end{matrix}\right.\) ( TM)

Vậy ....................................

a. (21 - 1) x (21 - 2) x (21 - 3) x ... x (21 - 21)

= 20 x 19 x 18 x ... x 0

= 0

b. 3 x 27 x 8 + 4 x 35 x 6 + 2 x 38 x 12

= (3 x 8) x 27 + (4 x 6) x 35 + (2 x 12) x 38

= 24 x 27 + 24 x 35 + 24 x 38

= 24 x (27 + 35 + 38)

= 24 x100

= 2400

c. A = (1001 + 1002 + 1003 +... + 2009) x (360 x 87 - 360 x 32 - 360 x 55)

       = (1001 + 1002 + 1003 + ... + 2009) x [360 x (87 - 32 - 55)]

       = (1001 + 1002 + 1003 + ... + 2009) x (360 x 0)

       = (1001 + 1002 + 1003 + ... + 2009) x 0

        = 0 

Mình cảm ơn bạn nhiều :!!!