Bài 4:

a: Ta có: \(-\left|x+1.1\right|\le0\forall x\)

\(\Leftrightarrow-\left|x+1.1\right|+1.5\le1.5\forall x\)

Dấu '=' xảy ra khi x=-1,1

b: Ta có: \(-4\left|x-2\right|\le0\forall x\)

\(\Leftrightarrow-4\left|x-2\right|+10\le10\forall x\)

Dấu '=' xảy ra khi x=2

Ta có :

\(\left(2x^2-3x+1\right)-\left(2x^2-3x+4\right)=0\)

\(\Leftrightarrow2x^2-3x+1-2x^2+3x-4=0\)

\(\Leftrightarrow-3=0\left(ktm\right)\)

\(\Leftrightarrow x\in\varnothing\)

ok

Ok

các bn giúp mink nha

Trả lời: 

\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+9\right)+\left(x+10\right)=240\)

\(\Leftrightarrow\left(x+x+x+...+x+x\right)+\left(1+2+3+...+9+10\right)=240\)

\(\Leftrightarrow10x+\left(10+1\right)\times\left[\left(10-1\right)\div1+1\right]\div2=240\)

\(\Leftrightarrow10x+11\times10\div2=240\)

\(\Leftrightarrow10x+55=240\)

\(\Leftrightarrow10x=185\)

\(\Leftrightarrow x=18,5\)

Vậy \(x=18,5\)

( x+1 )+( x+2 )+...+( x+10 ) = 240

= x+1 + x+2 + x+3 +...+ x+9 + x+10 = 240

= ( x+x+x+...+x ) + ( 1+2+3+...+9+10 ) = 240

= 10.x + 55 = 240

   10.x = 240-55

   10.x = 185

     x  = 185 : 10

    x  = 18,5

Đk:\(-4\le x\le1.\)

Đặt \(\sqrt{1-x}=a,\sqrt{4+x}=b.\)

\(\Rightarrow\hept{\begin{cases}a+b=3\\a^2+b^2=5\end{cases}\Leftrightarrow\hept{\begin{cases}\left(a+b\right)^2=9\\a^2+b^2=5\end{cases}\Rightarrow}ab=2\Rightarrow\left(a-b\right)^2=1.\Rightarrow\orbr{\begin{cases}a-b=1\\a-b=-1\end{cases}\Rightarrow}\orbr{\begin{cases}a=2,b=1\\a=1,b=2\end{cases}}.}\)

Từ đó suy ra x=-3,x=0

Giải thích các bước giải:

 M= (7201272012+7979-1414)÷(5959-312312-1212 

= 2405452724054527 ÷ (−736−736)

= 2405452724054527 × (−367−367)

= −96203521−96203521 

Chúc bạn học tốt !

là sao bn

ai đúng mik cho 3 k

\(\left(4x-1\right)^3=\frac{-1}{27}\)

\(\Rightarrow\left(4x-1\right)^3=\left(\frac{-1}{3}\right)^3\)

\(\Rightarrow4x-1=\frac{-1}{3}\)

\(\Rightarrow4x=\frac{-1}{3}+1\)

\(\Rightarrow4x=\frac{2}{3}\)

\(\Rightarrow x=\frac{2}{3}:4\)

\(\Rightarrow x=\frac{1}{6}\)