`!`

\(a,\dfrac{8}{9}\times\dfrac{7}{5}-\dfrac{7}{9}\times\dfrac{2}{5}+\dfrac{2}{9}\\ =\dfrac{8}{9}\times\left(\dfrac{7}{5}-\dfrac{2}{5}\right)+\dfrac{2}{9}\\ =\dfrac{8}{9}\times\dfrac{5}{5}+\dfrac{2}{9}\\ =\dfrac{8}{9}+\dfrac{2}{9}\\ =\dfrac{10}{9}\)

\(b,\dfrac{5}{9}\times\dfrac{1}{4}+\dfrac{4}{9}\times\dfrac{3}{12}\\ =\dfrac{5}{9}\times\dfrac{1}{4}+\dfrac{4}{9}\times\dfrac{1}{4}\\ =\dfrac{1}{4}\times\left(\dfrac{5}{9}+\dfrac{4}{9}\right)\\ =\dfrac{1}{4}\times\dfrac{9}{9}\\ =\dfrac{1}{4}\)

mik ns cho pn cách làm các bài này nhé 

=>(x+1)²=2²

=>x+1=2

=>x=2-1=1

Vậy x=1

          (x+1)²=4

=>      (x+1)² - 2²=0

(X+1)^2=4

(X+1)^2=2^2

=>X+1=2

X=2-1

X=1

VẬY X=1

456,32 x 2 x 6 + 9 x 4 x 456,32+456,32 x 18 + 456,32 x 7 x 4 + 6 x 456,32

= ( 456,32 x 2 x 6 ) + ( 9 x 4 x 456,32 ) + ( 456,32 x 18 ) + ( 456,32 x7 x 4 ) + ( 6 x 456,32 )

= 45632

Đúng nha TRƯƠNG ĐỨC PHONG

TRƯƠNG ĐỨC PHONG TRƯƠNG ĐỨC PHONG

 456,32 x 2 x 6 + 9 x 4 x 456,32+456,32 x 18 + 456,32 x 7 x 4 + 6 x 456,32

= 456,32 x [(12 x 6) + (9 x 4) + 18 + (7 x 4) + 6]

= 456,32 x 100

= 45632

hẳn hoi nhé

kết quả là 1209101722

\(\frac{4}{3}-\frac{14}{x}=\frac{2}{5}\)

\(\frac{14}{x}=\frac{4}{3}-\frac{2}{5}\)

\(\frac{14}{x}=\frac{14}{15}\)

\(\Rightarrow\)\(x=15\)

TL:

\(\frac{4}{3}\)- \(\frac{14}{x}\)= \(\frac{2}{5}\)

\(\frac{14}{x}\)= \(\frac{4}{3}\)- \(\frac{2}{5}\)

\(\frac{14}{x}\)= \(\frac{14}{15}\)

   x = 15.

~HT~

\(\frac{4}{3}-\frac{14}{x}=\frac{2}{5}\)

\(\frac{14}{x}=\frac{4}{3}-\frac{2}{5}\)

\(\frac{14}{x}=\frac{14}{15}\)

\(x=15\)

\(x\left(x+3\right)\left(x-9\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x+3=0\\x-9=0\end{matrix}\right.\)

\(x+3=0\Leftrightarrow x=-3\)

\(x-9=0\Leftrightarrow x=9\)

Vậy pt trên có 3 nghiệm \(S=\left\{0;-3;9\right\}\)

\(x\left(x+3\right)\left(x-9\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x+3=0\\x-9=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-3\\x=9\end{matrix}\right.\)

\(\text{Vậy phương trình có tập nghiệm là }S=\left\{0;-3;9\right\}\)

Bài 1:

a)12,5 x (-5/7) + 1,5 x (-5/7)

=-5/7*(12,5+1,5)

=-5/7*14

=-10

b)(-1/4) x (6|2/11) + 3|9/11 x (-1/4)

=-1/4*(68/11+42/11)

=-1/4*10

=-5/2

c tương tự

d)\(\frac{9^8\cdot4^3}{27^4\cdot6^5}=\frac{\left(3^2\right)^8\cdot\left(2^2\right)^3}{\left(3^3\right)^4\cdot\left(2\cdot3\right)^5}=\frac{3^{16}\cdot2^6}{3^{12}\cdot2^5\cdot3^5}=\frac{3^{16}\cdot2^5\cdot2}{3^{16}\cdot3^1\cdot2^5}=\frac{2}{3}\)

Bài 2:

a)Ta có:

2⁸⁰⁰=(2⁸)¹⁰⁰=256¹⁰⁰

8²⁰⁰=(8²)¹⁰⁰=64¹⁰⁰

Vì 256¹⁰⁰>64¹⁰⁰ =>2⁸⁰⁰>8²⁰⁰

b)Ta có:

12⁴⁵=(12³)¹⁵=1728¹⁵

Vì 625¹⁵<1728¹⁵ =>625¹⁵<12⁴⁵

a) -5/7x(12,5+1,5)=-10

b) -1/4x (6I2/11+3I9/11) = -1/4x 10=-5/2

c) (-7/5 + -3/8 + -3/5+5/8): 2009/2010 = -7/4:2009/2010=-1005/574

d)3^16x 4^3/3^12x 6^5=3^4x4^3x6^5=......

bài 2)

2^800=2^4x200= 15^200> 8^200

=> 2^800>8^200

B) quên cách làm

dell   

bai o ban noi the co the ban la c ho day