9x+5.4 = 200                 4x-20 = 2^5:2^2                  2.3^x-5=157 

9x+ 20 = 200                 4x-20 = 2^3                       2.3^x=157+5

9x = 200-20                   4x-20 = 8                            2.3^x=162                

9x = 180                       4x = 8+20                         3^x=162:2

x= 180 : 9                     4x = 28                             3^x=81

x=2                              x = 28:4                    mà 3^4=81 => x=4

                                   x = 7

\(=5\cdot2^6+2^4\cdot5=5\cdot2^4\left(2^2+1\right)=80\cdot5=400\)

=5(4³+2⁴)

=5(64+16)

=5.80

=400

a) (4x+2x+18.5-10).3=66.5

=>4x+2x+18.5-10=22.5

=>6x+90-10=110

=>6x+80=110

=>6x=110-80

=>6x=30

=>x=30:6

=>x=5

b) 15+5.4+3.10+5.3=4.5.x

=>5(3+4+3.2+3)=4.5.x

=>3+4+3.2+3=4x

=>3+4+6+3=4x

=>16=4x

=>x=16:4

=>x=4

My ơi! Công thức thì chịu khó dùng hàm đi. Làm thế nó chép bài đấy!

rồi rồi thưa bà Linh! :)

1: Đa thức này ko phân tích được nha bạn

2: \(x^2+8x+7\)

\(=x^2+x+7x+7\)

\(=x\left(x+1\right)+7\left(x+1\right)\)

\(=\left(x+1\right)\left(x+7\right)\)

3: \(x^2-6x-16\)

\(=x^2-8x+2x-16\)

\(=x\left(x-8\right)+2\left(x-8\right)\)

\(=\left(x-8\right)\left(x+2\right)\)

4: \(4x^2-8x+3\)

\(=4x^2-2x-6x+3\)

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

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

5: \(3x^2-11x+6\)

\(=3x^2-9x-2x+6\)

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

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

Có:\(\dfrac{25^5.4^2}{5^5.\left(-2\right)^5}=\dfrac{\left(5^2\right)^5.2^4}{5^5.\left(-2\right)^5}=\dfrac{5^{10}.2^4}{5^5.\left(-2\right)^5}=\dfrac{5^5}{-2}=\dfrac{3125}{2}\)

420 : [ 5. 2² - (20 : 5.4 - 13) +4]

=420 : [5.4 -(4.4 -13)+4]

=420 : [20 -(16 -13) +4]

=420 : [20-3 +4]

=420: [17+4]

=420 : 21          

= 20                                     

420 : [ 5. 2² - ( 20 : 5.4 -13 ) + 4 ]

= 420 : [ 5 . 4 - ( 4 . 4 - 13 ) + 4 ]

= 420 : ( 20 - 3 + 4 )

= 420 : ( 17 + 4 )

= 420 : 21

= 20

a: \(5^6:5^3+2^3:2^2\)

\(=5^3+2\)

=125+2

=127

b: \(3333:3+225:15\)

=1111+15

=1126

c: \(15\cdot2^3+4\cdot3^2-5\cdot7\)

\(=15\cdot8+4\cdot9-35\)

=120+36-35

=121

d: \(5\cdot4^2-18:3^2\)

\(=5\cdot16-18:9\)

=80-2=78

e: \(6^2:4\cdot3+2\cdot5^2\)

\(=36:4\cdot3+2\cdot25\)

=27+50

=77

f: \(80-\left(4\cdot5^2-3\cdot2^3\right)\)

=80-(100-24)

=80-76

=4