a) -9-25=(7-x)-(25+7)

<=> −9−25=7−x−25−7

<=> -9=7-x-7

<=> -9=-x

<=> x=9

b) (x-5)(x+8)=0

<=> x-5=0 hoặc x+8=0

<=> x=5 hoặc x=-8

d) Đề sai, x đâu???

...

\(c,0< \left|x-7\right|< 3\)

\(0< x-7< 3\)

\(7< x< 10\)

\(\Rightarrow x\in\left\{8;9\right\}\)

a) \(25-\left(25-x\right)=12+\left(42-65\right)\)

\(25-\left(25-x\right)=12+\left(-23\right)\)

\(25-\left(25-x\right)=-11\)

\(25-x=25-\left(-11\right)\)

\(25-x=36\)

\(x=25-36\)

\(x=-11\)

Làm 2 câu dài cho bạn nhá! Mấy câu ngắn tương tự!

a, \(25-\left(25-x\right)=12+\left(42-65\right)\)

\(\Rightarrow25-25+x=12+42-65\)

\(\Rightarrow x=-11\)

b, \(215+\left(-38\right)-54+90-\left(-48+x\right)=0\)

\(\Rightarrow215-38-54+90+48-x=0\)

\(\Rightarrow x=261\)

m, \(\left|x\right|-5=12\)

\(\Rightarrow\left|x\right|=17\Rightarrow\left\{{}\begin{matrix}x=-17\\x=17\end{matrix}\right.\)

Chúc bạn học tốt!!!

\(25-\left(25-x\right)=12+\left(42-65\right).\)

\(\Leftrightarrow25-25+x=12-23.\)

\(\Leftrightarrow x=-11.\)

Vậy \(x=-11.\)

25 - ( 25 - x ) = 12 + ( 42 - 65 )

25 - ( 25 - x ) = 12 + (-23)

25 - ( 25 - x ) = -11

25 - x = 25 - (-11)

25 - x = 36

x = 25 - 36

x = -11

25 - (25 - x) = 12 + (42 - 65)

25 - 25 + x = 12 + (-23)

x = - 11

\(25-\left(25-x\right)=12+\left(42-65\right).\)

\(\Leftrightarrow25-25+x=12-23.\)

\(\Leftrightarrow x=-11.\)

Vậy \(x=-11.\)

25 x 34 + 65 x 75 - 35 x 86 + 65 x 45

= 5 x 17 x 10 + 65 x (75 + 45) - 7 x 43 x 10

= 85 x 10 + 780 x 10 - 301 x 10

= 10 x (85 + 780 - 301)

= 10 x 564

= 5640

Câu 1: 

a: =126+5=131

b: =-564-724+564+224=-500

c: =3x25+2-8

=75+2-8

=77-8

=69

d: =1024:32+140:70-49

=32-49+2

=-15

cảm ơn nha

a) \(-65-\left(x+15\right)+105=0\)

\(-65-\left(x+15\right)=-105\)

\(x+15=-65-\left(-105\right)\)

\(x+15=40\)

\(x=25\)

b) |-6| + (-9) - (x+1) = 7

-3- (x+1) =7

       x+1  = -10

       x      = -11

c)\(\left|5-x\right|+\left(-25+7\right)=-3-\left(-10\right)\)

    \(\left|5-x\right|+\left(-18\right)=7\)

    \(\left|5-x\right|=25\)

\(\Rightarrow\orbr{\begin{cases}5-x=25\\5-x=-25\end{cases}\Rightarrow\orbr{\begin{cases}x=-20\\x=30\end{cases}}}\)

d) \(28-\left|x+6\right|+\left(-2\right)=0\)

\(28-\left|x+6\right|=2\)

\(\left|x+6\right|=26\)

\(\Rightarrow\orbr{\begin{cases}x+6=26\\x+6=-26\end{cases}\Rightarrow\orbr{\begin{cases}x=20\\x=-32\end{cases}}}\)

e) \(x-\left(13-15\right)=5+\left(10-x\right)-\left(-1\right)\)

\(x+2=5+10-x+1\)

\(x+2=16-x\)

\(x+x=16-2\)

\(2x=14\)

\(x=7\)

f) \(-120-\left(x-5\right)=125\)

\(x-5=-120-125\)

\(x-5=-245\)

\(x=-240\)

g) \(10-\left(-5+2\right)+\left(-9\right)=\left(-20+7\right)-x\)

\(-16=-13-x\)

\(x=-13+16\)

\(x=3\)

=1068

1068