1, \(3x\left(x-7\right)+2x-14=0\)

\(\Rightarrow3x\left(x-7\right)+2\left(x-7\right)=0\)

\(\Rightarrow\left(x-7\right)\left(3x+2\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x=7\\x=\frac{-2}{3}\end{cases}}\)

2, \(x^3+3x^2-\left(x+3\right)=0\)

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

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

\(\Rightarrow\left(x+3\right)\left(x-1\right)\left(x+1\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x=-3\\x=\pm1\end{cases}}\)

3, \(15x-5+6x^2-2x=0\)

\(\Rightarrow\left(15x-5\right)+\left(6x^2-2x\right)=0\)

\(\Rightarrow5\left(3x-1\right)+2x\left(3x-1\right)=0\)

\(\Rightarrow\left(3x-1\right)\left(5+2x\right)=0\)

\(\Rightarrow\orbr{\begin{cases}3x-1=0\\5+2x=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{1}{3}\\x=\frac{-5}{2}\end{cases}}\)

4, \(5x-2-25x^2+10x=0\)

\(\Rightarrow\left(5x-25x^2\right)-\left(2-10x\right)=0\)

\(\Rightarrow5x\left(1-5x\right)-2\left(1-5x\right)=0\)

\(\Rightarrow\left(1-5x\right)\left(5x-2\right)=0\)

\(\Rightarrow\orbr{\begin{cases}1-5x=0\\5x-2=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{1}{5}\\x=\frac{2}{5}\end{cases}}\)

a, \(x^3+3x^2-\left(x+3\right)=0\Leftrightarrow x^2\left(x+3\right)-\left(x+3\right)=0\)

\(\Leftrightarrow\left(x-1\right)\left(x+1\right)\left(x+3\right)=0\Leftrightarrow x=1;x=-1;x=-3\)

b, \(15x-5+6x^2-2x=0\Leftrightarrow5\left(3x-1\right)+2x\left(3x-1\right)=0\)

\(\Leftrightarrow\left(2x+5\right)\left(3x-1\right)=0\Leftrightarrow x=-\frac{5}{2};x=\frac{1}{3}\)

c, \(5x-2-25x^2+10x=0\)

\(\Leftrightarrow\left(5x-2\right)-5x\left(5x-2\right)=0\Leftrightarrow\left(1-5x\right)\left(5x-2\right)=0\Leftrightarrow x=\frac{2}{5};x=\frac{1}{5}\)

= 1/5 nha

1. \(4x^2-49=0\)

\(\Leftrightarrow\left(2x+7\right)\left(2x-7\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}2x+7=0\Leftrightarrow x=-\dfrac{7}{2}\\2x-7=0\Leftrightarrow x=\dfrac{7}{2}\end{matrix}\right.\)

Vậy: \(x=-\dfrac{7}{2}\) hoặc \(x=\dfrac{7}{2}\)

===========

2. \(x^2+36=12x\)

\(\Leftrightarrow x^2-12x+36=0\)

\(\Leftrightarrow\left(x-6\right)^2=0\)

\(\Leftrightarrow x=6\)

Vậy: \(x=6\)

===========

3. \(10\left(x-5\right)-8x\left(5-x\right)=0\)

\(\Leftrightarrow10\left(x-5\right)+8x\left(x-5\right)=0\)

\(\Leftrightarrow\left(x-5\right)\left(10+8x\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x-5=0\Leftrightarrow x=5\\10+8x=0\Leftrightarrow x=-\dfrac{5}{4}\end{matrix}\right.\)

Vậy: \(x=5\) hoặc \(x=-\dfrac{5}{4}\)

1: Ta có: \(4x^2-49=0\)

\(\Leftrightarrow\left(2x-7\right)\left(2x+7\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{7}{2}\\x=-\dfrac{7}{2}\end{matrix}\right.\)

2: Ta có: \(x^2+36=12x\)

\(\Leftrightarrow x^2-12x+36=0\)

\(\Leftrightarrow\left(x-6\right)^2=0\)

\(\Leftrightarrow x-6=0\)

hay x=6

Trả lời:

\(1,3x\left(x-7\right)+2x-14=0\)

\(\Leftrightarrow3x\left(x-7\right)+2\left(x-7\right)=0\)

\(\Leftrightarrow\left(x-7\right)\left(3x+2\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x-7=0\\3x+2=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=7\\x=-\frac{2}{3}\end{cases}}}\)

Vậy x = 7; x = - 2/3 là nghiệm của pt.

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

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

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

\(\Leftrightarrow\orbr{\begin{cases}x+3=0\\x^2-1=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-3\\x=\pm1\end{cases}}}\)

Vậy x = - 3; x = 1; x = - 1 là nghiệm của pt.

\(3,15x-5+6x^2-2x=0\)

\(\Leftrightarrow5\left(3x-1\right)+2x\left(3x-1\right)=0\)

\(\Leftrightarrow\left(3x-1\right)\left(5+2x\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}3x-1=0\\5+2x=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{3}\\x=-\frac{5}{2}\end{cases}}}\)

Vậy x = 1/3; x = - 5/2 là nghiệm của pt.

a:  =>x-16=74

nên x=90

Tính nhanh :

= -167 x 83 + (-167) x 17 - 33

= (-167) x (83+17) - 33

= (-167) x 100 - 33

= -16700-33 = -16733

Tìm x :

a, => 49-x^2=0 ( vì x^2+1 > 0 )

=> x^2=49

=> x=7 hoặc x=-7

b, => 3-x=0 hoặc 8-x=0

=> x=3 hoặc x=8

c, => x+2=0 hoặc x-3=0

=> x=-2 hoặc x=3

Tk mk nha

t làm Ngếu Ngáo câu A. đúng thì đúng mà sai thi thôi nhé 

(-100-67) x (80+3)+(100+67) x(-10-7)-33   ( phá ngoặc)

\(-100-67\times80+3+100+67\times\left(-10\right)-7-33\) ( rút gọn)

\(\left(80+3-40\right)\times\left(-10\right)\) ( tính ) 

\(43\times\left(-10\right)=-430\)

ko biêt đúng hay sai đâu kk 

\(\left(-167\right).83+167.\left(-17\right)-33\)

\(=167.\left(-83-17\right)-33\)

\(=167.\left(-100\right)-33\)

\(=-16700-33\)

\(=-16733\)

\(\left(x^2+1\right)\left(49-x^2\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x^2+1=0\\49-x^2=0\end{cases}}\Rightarrow\orbr{\begin{cases}x^2=-1\\x^2=49\end{cases}}\Rightarrow\orbr{\begin{cases}x\in\varnothing\\x=\pm7\end{cases}}\)

vậy \(x=\pm7\)

\(\left(3-x\right)\left(8-x\right)>0\)

\(\Leftrightarrow\hept{\begin{cases}3-x>0\\8-x>0\end{cases}}\) hoặc \(\hept{\begin{cases}3-x< 0\\8-x< 0\end{cases}}\)

\(\Leftrightarrow\hept{\begin{cases}-x>-3\\-x>-8\end{cases}}\)hoặc \(\hept{\begin{cases}-x< -3\\-x< -8\end{cases}}\)

\(\Leftrightarrow\hept{\begin{cases}x< 3\\x< 8\end{cases}}\) hoặc \(\hept{\begin{cases}x>3\\x>8\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x< 3\\x>8\end{cases}}\)

vậy \(\orbr{\begin{cases}x< 3\\x>8\end{cases}}\)

\(x+xy+x=9\)

\(2x+xy=9\)

\(x\left(y+2\right)-9=0\)

\(\left(x-\frac{1}{2}\right)^2=0\)

\(\Leftrightarrow\left(x-\frac{1}{2}\right)^2=0^2\)

\(\Leftrightarrow x-\frac{1}{2}=0\)

\(\Leftrightarrow x=\frac{1}{2}\)

Vậy x = 1/2

\(\left(x-2\right)^2=1\)

\(\Leftrightarrow\left(x-2\right)^2=1^2\)

\(\Leftrightarrow x-2=1\)

\(\Leftrightarrow\orbr{\begin{cases}x-2=1\\x-2=-1\end{cases}\Leftrightarrow\orbr{\begin{cases}x=3\\x=1\end{cases}}}\)

Vậy x = 3 hoặc x = 1

\(\left(2x-1\right)^3=-8\)

\(\Leftrightarrow\left(2x-1\right)^3=\left(-2\right)^3\)

\(\Leftrightarrow2x-1=-2\)

<=> 2x = -1

<=> x = -0,5

Vậy x = -0,5

\(\left(x-\frac{1}{2}\right)^2=0\)

\(x-\frac{1}{2}=0\)

\(x=\frac{1}{2}\)

\(\left(x-2\right)^2=1\)

\(\Leftrightarrow\orbr{\begin{cases}x-2=1\\x-2=-1\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=1+2\\x=-1+2\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=3\\x=1\end{cases}}\)

Vậy\(x\in\left\{3;1\right\}\)
\(\left(2x-1\right)^3=-8\)

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

\(2x-1=-2\)

\(2x=\left(-2\right)+1\)

\(2x=-1\)

\(x=-1\times2\)

\(x=-2\)

\(x\left(\frac{1}{2}\right)^2=\frac{1}{16}\)

\(x\left(\frac{1}{2}\right)^2=\left(\frac{1}{4}\right)^2\)

\(\Leftrightarrow\orbr{\begin{cases}x\frac{1}{2}=\frac{1}{4}\\x\frac{1}{2}=-\frac{1}{4}\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{4}:\frac{1}{2}\\x=-\frac{1}{4}:\frac{1}{2}\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=\frac{1}{2}\\x=-\frac{1}{2}\end{cases}}}\)

\(49\times7^x=2401\)

   \(7^x=2401:49\)

\(7^x=49\)

\(7^x=7^2\)

\(\Rightarrow x=2\)

\(2x^x-15=17\)

\(2x^x=17+15\)

\(2x^x=32\)

\(2x^x=2^5\)

\(\Rightarrow x\times x=5\)

\(\Rightarrow x^2=5\)

\(2^x+3\times2^x=32\)

\(2^x\times\left(3+1\right)=32\)

\(2^x\times4=32\)

\(2^x=32:4\)

\(2^x=8\)

\(2^x=2^3\)

\(\Rightarrow x=3\)

\(2x\left(x-\frac{1}{7}\right)=0\)

\(x\left(x-\frac{1}{7}\right)=0:2\)

\(x\left(x-\frac{1}{7}\right)=0\)

\(x\times x-x\times\frac{1}{7}=0\)

\(x^2-x\frac{1}{7}=0\)

\(x-x=0:\frac{1}{7}\)

\(x-x=0\)

\(\Rightarrow x=0\)

a, 27³ : 3⁵  =  ( 3³)³ : 3⁵ = 3⁹ : 3⁵ = 3⁴

b, 7² . 343 . 49³⁰ = 7². 7³.(7²)³  = 7¹¹

c, 625 : 5³ = 5⁴ : 5³ =  5

d, 1 000 000 : 10³ = 10⁶ . 10³ = 10³

e, 11⁵ : 121= 11⁵ : 11² = 11³

f, 8⁷ : 64 :8 = 8⁷ : 8² : 8¹ = 8⁴

i, 1024 . 16 : 2⁶  = 2¹⁰ . 2³ : 2⁶ = 2⁷

B2:

 số chính phương là:

4 ; 121 ; 196 ; 225.

Bài 2 :

Số chính phương là :

\(4=2^2\)

\(121=11^2\)

\(196=14^2\)

\(225=25^2\)