a: =>7(x-5)>0

=>x-5>0

=>x>5

b: =>x-1 thuộc {1;-1;11;-11}

=>x thuộc {2;0;12;-10}

c: =>x+1+7 chia hết cho x+1

=>x+1 thuộc {1;-1;7;-7}

=>x thuộc {0;-2;6;-8}

d: =>(x+2)(x-5)<0

=>-2<x<5

a:(- 7) . ( 5 – x) < 0

=>7(x-5)>0

=>x-5>0

=>x>5

b:11 ⁝ x – 1

=>x-1 thuộc {1;-1;11;-11}

=>x thuộc {2;0;12;-10}

c: x + 8 ⁝ x + 1

=>x+1+7 chia hết cho x+1

=>x+1 thuộc {1;-1;7;-7}

=>x thuộc {0;-2;6;-8}

d: (x + 2) . (5 – x) > 0

=>(x+2)(x-5)<0

=>-2<x<5

\(1) 420+65.4=(x+175):5+30\)

\(\implies 420+260=(x+175):5+30\)

\(\implies 680=(x+175):5+30\)

\(\implies 650=(x+175):5\)

\(\implies 650.5-175=x\)

\(\implies 3075=x\)

\(2)x-4867=(175.2050.70):25+23\)

\(\implies x-4867=1004500+23\)

\(\implies x-4867=1004523\)

\(\implies x=1009390\)

\(3) 134-[(96-7x):4-2]=126\)

\(\implies (96-7x):4-2=8\)

\(\implies(96-7x):4=10\)

\(\implies 96-7x=40\)

\(\implies 7x=56\)

\(\implies x=8\)

\(4) 4-\{100-[(100-5x):8-5]:10\}:25=0\)

\(\implies 4-\{100-[(100-5x):8-5]:10\}=0\)

\(\implies 100-[(100-5x):8-5]:10=4\)

\(\implies 100-[(100-5x):8-5]=40\)

\(\implies (100-5x):8-5=60\)

\(\implies (100-5x):8=65\)

\(\implies 100-5x=520\)

\(\implies 5x=-420\)

\(\implies x=-84\)

~ Hok tốt a~

ai nua cac ban

ban nao biet thi minh h

\(a,\Leftrightarrow\left(5x+1\right)\left(x-4\right)-\left(x-4\right)=0\\ \Leftrightarrow\left(x-4\right)\left(5x+1-x\right)=0\\ \Leftrightarrow5x\left(x-4\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=4\end{matrix}\right.\\ b,\Leftrightarrow2x^2-10x-2x^2-3x=26\\ \Leftrightarrow-13x=26\\ \Leftrightarrow x=-2\\ c,\Leftrightarrow x^3+1-x^3+3x=15\\ \Leftrightarrow3x=14\\ \Leftrightarrow x=\dfrac{14}{3}\)

\(d,\Leftrightarrow x^3-5x+2x^2-10+5x-2x^2-17=0\\ \Leftrightarrow x^3-27=0\\ \Leftrightarrow x^3=27\\ \Leftrightarrow x=3\)

a) \(=x\left(x-5\right)+\left(x-5\right)^2=\left(x-5\right)\left(x+x-5\right)=\left(x-5\right)\left(2x-5\right)\)

b) \(=x^2-2.x.10+10^2=\left(x-10\right)^2\)

c) \(=x\left(x+3\right)+2\left(x+3\right)=\left(x+3\right)\left(x+2\right)\)

Em bấm vào biểu tượng \(\sum\) trên thanh công cụ và gõ phân số để mn dễ hỗ trợ nhé!

`(x^2+x-6)/(x^2+4x+3):(x^2-10x+25)/(x^2-4x-5)(x ne -1,x ne 5,x ne -3)`

`=((x-2)(x+3))/((x+1)(x+3)):(x-5)^2/((x+1)(x-5))`

`=(x-2)/(x+1):(x-5)/(x+1)`

`=(x-2)/(x-5)`

\(\dfrac{x^2+x-6}{x^2+4x+3}=\dfrac{\left(x+3\right)\left(x-2\right)}{\left(x+3\right)\left(x+1\right)}=\dfrac{x-2}{x+1}\)

\(\dfrac{x^2-10x+25}{x^2-4x-5}=\dfrac{\left(x-5\right)^2}{\left(x-5\right)\left(x+1\right)}=\dfrac{x-5}{x+1}\)

a) x = 200.

b) x = 70.

c) x = 0.

d) x = 0.

a) x = 200.

b) x = 70.

c) x = 0.

d) x = 0.

a) x = 200

b) x = 70

c) x = 0

d) x = 0

\(\left(x-1\right)^2=5^2\\\Rightarrow x-1=5\\ \Rightarrow x=5+1=6\)