9 x 1 = 9

9 x 5 = 45

9 x 4 = 32

9 x 10 = 90

9 x 2 = 18

9 x 7 = 63

9 x 8 = 72

9 x 0 = 0

9 x 3 = 27

9 x 9 = 81

9 x 6 = 54

0 x 9 = 0

= 9                            = 45                                      = 36

dễ mà bạn gì ơi

9 x 4 = 36

9 x 2 = 18

9 x 5 = 40

9 x 10 = 90

9 x 1 = 9

9 x 7 = 63

9 x 8 = 72

0 x 9 = 0

9 x 3 = 27

9 x 6 = 54

9 x 9 = 81

9 x 0 = 0

a) 9 x 1=9                   9 x 4=36                   9 x 7=63

b) 9 x 2=18                 9 x 5=45                   9 x 8=72

c) 9 x 3=27                 9 x 6=54                   9 x 981

d) 9 x 10=90               9 x 0=0                     0 x 9=0

a)= ( 81 , 6 x 27 , 3 – 17 , 3 x 81 , 6 ) x 0

=0 ( vì 0 nhân với số nào cũng bằng 0)

b)= ( 13 , 75 – 0 , 48 x 5 ) x ( 42 , 75 : 3 + 2 , 9 ) x ( 9-9)

= ( 13 , 75 – 0 , 48 x 5 ) x ( 42 , 75 : 3 + 2 , 9 ) x 0

= 0 ( vì 0 nhân với số nào cũng bằng 0)

c)=( 792 , 81 x 0 , 25 + 792 , 81 x 0 , 75 ) x 0

=0 ( vì 0 nhân với số nào cũng bằng 0 )

a ) ( 81 , 6 x 27 , 3 – 17 , 3 x 81 , 6 ) x ( 32 x 11 - 3200 x 0 , 1 - 32 )

= ( 81 , 6 x 27 , 3 – 17 , 3 x 81 , 6 ) x ( 352 - 320 - 32 )

= ( 81 , 6 x 27 , 3 – 17 , 3 x 81 , 6 ) x 0

= 0.

b ) ( 13 , 75 – 0 , 48 x 5 ) x ( 42 , 75 : 3 + 2 , 9 ) x ( 1 , 8 x 5 – 0 , 9 x 10 )

= ( 13 , 75 – 0 , 48 x 5 ) x ( 42 , 75 : 3 + 2 , 9 ) x ( 9 - 9 )

= ( 13 , 75 – 0 , 48 x 5 ) x ( 42 , 75 : 3 + 2 , 9 ) x 0

= 0

c ) ( 792 , 81 x 0 , 25 + 792 , 81 x 0 , 75 ) x ( 11 x 9 – 900 x 0 , 1 – 9 )

= ( 792 , 81 x 0 , 25 + 792 , 81 x 0 , 75 ) x ( 99 - 90 - 9 )

= ( 792 , 81 x 0 , 25 + 792 , 81 x 0 , 75 ) x 0

= 0.

Hok tốt !

a)32 x 11 -3200x 0,1 -32

=32x11-32x100x0,1-32

=32x(11-10-1)=32x0=0

nên(81,6x27,3-17,3x81,6)x(32x11-3200x0,1-32)

=(81,6x27,3-17,3x81,6)x0

=0

b)1,8x5 -0,9x10=1,8x5-0,9x2x5

=1,8x5-1,8x5

=0

nên (13,75-0,48 x 5)x(42,75:3+2,9)x(1,8x5-0,9x10)=0

c)(792,81x0,25+792,81x0,75)x(11x9-900x0,1-9)

=792,81x(0,25+0,75)x(99-90-9)

=792,81x1x0

=0

1) Rút gọn biểu thức M: M = (2√x)/(√x - 3) - (x + 9√x)/(x - 9) = (2√x(x - 9) - (x + 9√x)(√x - 3))/(√x - 3)(x - 9) = (2x√x - 18√x - x√x + 9x + 9x - 27√x - 9√x + 27 )/(√x - 3)(x - 9) = (2x√x - 36√x + 27x)/(√x - 3)(x - 9) = (x(2√x - 36) + 27x) /(√x - 3)(x - 9) = (x(2√x - 36 + 27))/(√x - 3)(x - 9) = (x(2√x - 9))/( √x - 3)(x - 9) Do đó biểu thức M Rút gọn là: M = (x(2√x - 9))/(√x - 3)(x - 9) 2) Tìm các giá trị của x ă mãn M/N.(căn x + 3) = 3x - 5: Ta có phương trình: M/N.(căn x + 3) = 3x - 5 Đặt căn x + 3 = t, t >= 0, ta có x = t^2 - 3 Thay x = t^2 - 3 vào biểu thức M/N, ta có: M/N = [(t^2 - 3)(2√(t^2 - 3) - 9)]/[(t^2 - 3 + 5)t] = [(2(t^2 - 3) √(t^2 - 3) - 9(t^2 - 3))]/(t^3 + 2t - 3t - 6) = [2(t^2 - 3)√(t^2 - 3) - 9(t^2 - 3)]/(t(t - 1)(t + 2)) Đặt u = t^2 - 3, ta có: M/N = [2u√u - 9u]/((u + 3)(u + 2)) = [u(2√u - 9)]/((u + 3)(u + 2)) Đặt v = √u, ta có: M/N = [(v^ 2 + 3)(2v - 9)]/[((v^2 + 3)^2 - 3)(v^2 + 2)] = [(2v^3 - 18v + 6v - 54)]/[ ( (v^4 + 6v^2 + 9) - 3)(v^2 + 2)] = (2v^3 - 12v - 54)/(v^4 + 6v^2 + 6v^2 - 9v^2 + 18) = (2v^3 - 12v - 54)/(v^4 + 12v^2 + 18) Ta cần tìm các giá trị của v đối xứng phương trình M/N = 3x - 5: (2v^3 - 12v - 54)/(v^4 + 12v^2 + 18) = 3(t^2 - 3) - 5 (2v ^3 - 12v - 54)/(v^4 + 12v^2 + 18) = 3t^ 2 - 14 (2v^3 - 12v - 54) = (v^4 + 12v^2 + 18)(3t^2 - 14) Tuy nhiên, từ t = √(t^2 - 3), ta có v = √u = √(t^2 - 3) => (2(v^2)^3 - 12(v^2) - 54) = ((v^2)^4 + 12(v^2)^2 + 18) (3(v^2 - 3) - 14) => 2v^

0

ko có

1100000000

<

>

ko t.tại

\(1,\Leftrightarrow x\left(x-9\right)=0\Leftrightarrow\left[{}\begin{matrix}x=9\\x=0\end{matrix}\right.\\ 2,\Leftrightarrow x^2-4x-x^2=7\Leftrightarrow-4x=7\Leftrightarrow x=-\dfrac{7}{4}\\ 3,\Leftrightarrow3x+2x-10=5\Leftrightarrow5x=15\Leftrightarrow x=3\\ 4,\Leftrightarrow\left(5x-1\right)\left(5x+1\right)=0\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{5}\\x=-\dfrac{1}{5}\end{matrix}\right.\\ 5,\Leftrightarrow\left(x-2\right)\left(3x-5\right)=0\Leftrightarrow\left[{}\begin{matrix}x=2\\x=\dfrac{5}{3}\end{matrix}\right.\\ 6,\Leftrightarrow\left(x-7\right)\left(3x+4\right)=0\Leftrightarrow\left[{}\begin{matrix}x=7\\x=-\dfrac{4}{3}\end{matrix}\right.\)

\(7,\Leftrightarrow\left(2x-3\right)\left(2x+3\right)=0\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=-\dfrac{3}{2}\end{matrix}\right.\\ 8,\Leftrightarrow\left(x-4\right)\left(10x+2\right)=0\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{5}\\x=4\end{matrix}\right.\\ 9,\Leftrightarrow2x^2-5x-2x^2=0\Leftrightarrow x=0\\ 10,\Leftrightarrow2x\left(x-2\right)=0\Leftrightarrow\left[{}\begin{matrix}x=0\\x=2\end{matrix}\right.\\ 11,\Leftrightarrow\left(4x-3\right)\left(3-2x\right)=0\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{4}\\x=\dfrac{3}{2}\end{matrix}\right.\\ 12,\Leftrightarrow2x^2-10x-2x^2=3\Leftrightarrow-10x=3\Leftrightarrow x=-\dfrac{3}{10}\)

\(1,\Leftrightarrow x\left(x-9\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=9\end{matrix}\right.\\ 2,\Leftrightarrow x^2-4x-x^2=7\\ \Leftrightarrow-4x=7\\ \Leftrightarrow x=\dfrac{-7}{4}\\ 3,\Leftrightarrow3x+2x-10=5\\ \Leftrightarrow5x=15\\ \Leftrightarrow x=3\\ 4,\Leftrightarrow\left(5x-1\right)\left(5x+1\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{5}\\x=-\dfrac{1}{5}\end{matrix}\right.\)

\(5,\Leftrightarrow\left(x-2\right)\left(3x-5\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=2\\x=\dfrac{5}{3}\end{matrix}\right.\\ 6,\Leftrightarrow\left(3x+4\right)\left(x-7\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{4}{3}\\x=7\end{matrix}\right.\\ 7,\Leftrightarrow\left(2x-3\right)\left(2x+3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=-\dfrac{3}{2}\end{matrix}\right.\)

\(8,\Leftrightarrow10x\left(x-4\right)+2\left(x-4\right)=0\\ \Leftrightarrow\left(x-4\right)\left(10x+2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=4\\x=-\dfrac{1}{5}\end{matrix}\right.\\ 9,\Leftrightarrow2x^2-5x-2x^2=0\\ \Leftrightarrow-5x=0\\ \Leftrightarrow x=0\\ 10,\Leftrightarrow2x\left(x-2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=2\end{matrix}\right.\)

\(11,\Leftrightarrow\left(2x-3\right)\left(4x-3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=\dfrac{3}{4}\end{matrix}\right.\\ 12,\Leftrightarrow2x^2-10x-2x^2=3\\ \Leftrightarrow-10x=3\\ \Leftrightarrow x=-\dfrac{3}{10}\)

1) \(x^2-9x=0\Rightarrow x\left(x-9\right)=0\Rightarrow x=0;9\)

2) \(x\left(x-4\right)-x^2=7\Rightarrow-4x=7\Rightarrow x=-\dfrac{7}{4}\)

3) \(3x+2\left(x-5\right)=5\Rightarrow5x-10=5\Rightarrow5x=15\Rightarrow x=3\)

4) \(25x^2-1=0\Rightarrow x^2=\dfrac{1}{25}\Rightarrow x=\pm\dfrac{1}{5}\)

5) \(3x\left(x-2\right)-5\left(x-2\right)=0\Rightarrow\left(x-2\right)\left(3x-5\right)=0\Rightarrow x=2;\dfrac{5}{3}\)

6) \(3x\left(x-7\right)+4\left(x-7\right)\Rightarrow\left(3x+4\right)\left(x-7\right)=0\Rightarrow x=-\dfrac{4}{3};7\)

7) \(4x^2-9=0\Rightarrow x^2=\dfrac{9}{4}\Rightarrow x=\pm\dfrac{3}{2}\)

8) \(10x\left(x-4\right)+2x-8=0\Rightarrow2\left(x-4\right)\left(5x+1\right)=0\Rightarrow x=4;-\dfrac{1}{5}\)

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

10) \(2x^2-4x=0\Rightarrow2x\left(x-2\right)=0\Rightarrow x=0;2\)

11) \(2x\left(3-4x\right)+3\left(4x-3\right)=0\Rightarrow2x\left(4x-3\right)-3\left(4x-3\right)=0\Rightarrow\left(4x-3\right)\left(2x-3\right)=0\Rightarrow x=\dfrac{3}{4};\dfrac{3}{2}\)

12) \(2x\left(x-5\right)-2x^2=3\Rightarrow-10x=3\Rightarrow x=-\dfrac{3}{10}\)

a) \(\dfrac{3-\sqrt{x}}{x-9}=\dfrac{-\left(\sqrt{x}-3\right)}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}=-\dfrac{1}{\sqrt{x+3}}\)(\(x\ge0,x\ne9\))

b) \(\dfrac{x-5\sqrt{x}+6}{\sqrt{x}-3}=\dfrac{\left(\sqrt{x}-3\right)\left(\sqrt{x}-2\right)}{\sqrt{x}-3}=\sqrt{x}-2\left(x\ge0,x\ne9\right)\)

a) \(\dfrac{3-\sqrt{x}}{x-9}=\dfrac{3-\sqrt{x}}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)}=-\dfrac{1}{\sqrt{x}+3}\)

b) \(\dfrac{x-5\sqrt{x}+6}{\sqrt{x}-3}=\dfrac{\left(\sqrt{x}-2\right)\left(\sqrt{x}-3\right)}{\sqrt{x}-3}=\sqrt{x}-2\)

c) \(6-2x-\sqrt{9-6x+x^2}=6-2x-\sqrt{\left(3-x\right)^2}=6-2x-\left|3-x\right|\)

mà \(x< 3\Rightarrow3-x>0\Rightarrow6-2x-\left|3-x\right|=6-2x-3+x=3-x\)

a,\(\dfrac{3-\sqrt{x}}{x-9}\)

=\(-\dfrac{3-\sqrt{x}}{\left(3-\sqrt{x}\right)\left(3+\sqrt{x}\right)}\)

=\(-\dfrac{1}{3+\sqrt{x}}\)