a: 128-2x=-8-x

=>-2x+x=-8-128

=>-x=-136

=>x=136

b: \(x-\left(-15\right)\cdot2=55-7\cdot\left(-3\right)\)

=>x+30=55+21

=>x+30=76

=>x=76-30

=>x=46

c: \(66-\left\lbrack5-\left(-x\right)\right\rbrack=169\)

=>66-[5+x]=169

=>x+5=66-169=-103

=>x=-103-5

=>x=-108

d: (8-2x)(8+x)=0

=>2(4-x)(8+x)=0

=>(x-4)(x+8)=0

=>\(\left[\begin{array}{l}x-4=0\\ x+8=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=4\\ x=-8\end{array}\right.\)

e: \(7-\left\lbrack x^2+\left(-9\right)\right\rbrack=-20\)

=>\(x^2-9=7+20=27\)

=>\(x^2=36\)

=>\(\left[\begin{array}{l}x=6\\ x=-6\end{array}\right.\)

16 nha ban k di

14 hình tam giác

9 hình chư nhật

a: \(\Leftrightarrow\left(x-3\right)\left(5x-1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=\dfrac{1}{5}\end{matrix}\right.\)

b: \(\Leftrightarrow x\left(x-1\right)\left(x+1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=1\\x=-1\end{matrix}\right.\)

a: \(\Leftrightarrow\left(x-5\right)\left(x+1\right)\left(x-1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=5\\x=-1\\x=1\end{matrix}\right.\)

d: \(\Leftrightarrow\left(x+3\right)\left(x^2-4x+5\right)=0\)

\(\Leftrightarrow x+3=0\)

hay x=-3

Bài 1:

a: Ta có: \(48751-\left(10425+y\right)=3828:12\)

\(\Leftrightarrow y+10425=48751-319=48432\)

hay y=38007

b: Ta có: \(\left(2367-y\right)-\left(2^{10}-7\right)=15^2-20\)

\(\Leftrightarrow2367-y=1222\)

hay y=1145

Bài 2: 

Ta có: \(8\cdot6+288:\left(x-3\right)^2=50\)

\(\Leftrightarrow288:\left(x-3\right)^2=2\)

\(\Leftrightarrow\left(x-3\right)^2=144\)

\(\Leftrightarrow\left[{}\begin{matrix}x-3=12\\x-3=-12\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=15\\x=-9\end{matrix}\right.\)

a)  (x - 3)² - 5.(x - 2) + 5 = 0.

<=> x^2 - 6x + 9 - 5x + 10 + 5 = 0

<=> x^2 - 11x + 24 = 0

<=> (x-3)(x-8)=0

<=> x = 3 hoặc x = 8

b) (2x - 1)² - 3.(x - 2).(x + 2) - 25 = 0.

<=> 4x^2 - 4x + 1 - 3x^2 + 12 - 25 = 0

<=> x² - 4x - 12 = 0

<=> (x+2)(x-6) = 0

<=> x = -2 hoặc x = 6

a, x = 384

b, x = 161

c, x = 8

d, x = 15

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