\(-524.\left[23+\left(-45\right)\right]+524\left(-45+123\right)\)

\(=\left(-524\right).23+\left(-524\right)\left(-45\right)+524.\left(-45\right)+524.123\)

\(=524.\left(-23\right)+524.45+524.\left(-45\right)+524.123\)

\(=524\left(-23+45-45+123\right)=524.100=52400\)

\(3⋮\left(n-1\right)\Leftrightarrow n-1\inƯ\left(3\right)=\left\{-3,-1,1,3\right\}\)

\(\Leftrightarrow n\in\left\{-2,0,2,4\right\}\).

mn ơi! giải nhanh giúp em với ạ. em cần gấp

a. \(-3\le x< 5\Rightarrow x\in\left\{-3,-2,-1,0,1,2,3,4\right\}\)

b. \(n+1< x\le n+5\Rightarrow x\in\left\{n+2,n+3,n+4,n+5\right\}\)

c.\(-4< x+5\le1\Leftrightarrow-9< x\le-4\Leftrightarrow x\in\left\{-8,-7,-6,-5,-4\right\}\)

\(\Leftrightarrow\left(135-7x\right):9=105-97=8\)

\(\Leftrightarrow135-7x=8.9=72\)

\(\Leftrightarrow7x=135-72=63\)

\(\Leftrightarrow x=63:7=9\)

• tvcuong10122007
• 17/10/2020

Đáp án:

a, 105 - (135 - 7x) :9 = 97

⇒  (135 - 7x)  :9         =8

⇒            135 - 7x      =72

⇒                     7x       =63

⇒                            x  =9

\(\Leftrightarrow11^{7x}:11^{2x}=11^{12}\)

\(\Leftrightarrow11^{7x-2x}=11^{12}\)

\(\Leftrightarrow11^{5x}=11^{12}\)

\(\Rightarrow5x=12\)

\(\Leftrightarrow x=\frac{12}{5}\)

Bài 2 

a, -1/2              b, 1            c, -1/2           d, 1/2           e, 5^2/3           f, 1/3.7^2 

Bài 3 thì lâu quá r nên chị cũm chẳng nhớ nữa, sogi nhìu nha:v 

ok cảm ơn bạn