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\(\frac{45.\left(15+1\right)-17}{28+45.15}\)=  \(\frac{45.15+45-28}{28+45.15}\)

                         =  \(\frac{45.15+28}{28+45.15}\)

                         =  1

= 45.(15+1)-17/45.15+28

= 45.15+45-17/45.15+28

= 45.15+28/45.15+28

= 1

Tk mk nha

= 45.(15+1)-17/45.15+28

= 45.15+45-17/45.15+28

= 45.15+28/45.15+28

= 1

\(\frac{45.16-17}{45.15+28}\)

\(=\frac{720-17}{675+28}\)

\(=1\)

a)\(\frac{16.17-5}{16.16+11}=\frac{16.17-16+11}{16.16+11}\)\(=\frac{16.\left(17-1\right)+11}{16.16+11}=\frac{16.16+11}{16.16+11}=1\)

b) \(\frac{45.16-17}{28+45.15}=\frac{45.\left(15+1\right)-17}{28+45.15}\)\(=\frac{45.15+45-17}{28+45.15}=\frac{45.15+28}{28+45.15}=1\)

c) \(\frac{7256.4375-725}{3650+4375.7255}=\frac{\left(7255+1\right).4375-725}{3650+4375.7255}\)\(=\frac{7255.4375+4375-725}{3650+4375.7255}\)\(=\frac{7255.4375+3650}{3650+4375.7255}=1\)

Câu C nhớ sửa 725 thành 7255 nha !

                                                       Bài giải

\(a,\text{ }\frac{16\cdot17-5}{16\cdot16+11}=\frac{16\cdot16+16-5}{16\cdot16+11}=\frac{16\cdot16+11}{16\cdot16+11}=1\)

\(b,\text{ }\frac{45\cdot16-17}{28+45\cdot15}=\frac{45\cdot15+45-17}{45\cdot15+28}=\frac{45\cdot15+28}{45\cdot15+28}=1\)

\(c,\text{ }\frac{7256\cdot4375-725}{3650+4375\cdot7255}=\frac{4375\cdot7255+4375-725}{4375\cdot7255+3650}=\frac{4375\cdot7255+3650}{4375\cdot7255+3650}=1\)

Tính:
\(\frac{45\cdot16-17}{45\cdot15+28}\)

\(=\frac{45\cdot15+45-17}{45\cdot15+28}\)

\(=\frac{45\cdot15+28}{45\cdot15+28}=1.\)

Tìm x:
\(5^x+5^{x+2}=650\)

=>\(5^x+5^x\cdot25=650\)

=>\(5^x\cdot26=650\)

Dễ rồi nhá.

Bài 1 : Ta có : \(\frac{45.16-17}{45.15+28}=\frac{45.16-17}{45.15+45-17}=\frac{45.16-17}{45\left(15+1\right)-17}=\frac{45.16-17}{45.16-17}=1\)

Bài 2 : 

Ta có 5^x + 5^{x + 2} = 650

=> 5^x(1 + 5²) = 650

=> 5^x . 26 = 650

=> 5^x = 650 : 26

=> 5^x = 25

=> 5^x = 5²

=> x = 2

Cám ơn hai bạn nha !

A,      45.16-17=45.15+45-17=28+45.15

Giờ ta thấy cả 2 vế đều có 45.15

Mà

28=28suy ra 45.16-27=28+45.15

B, xét 3650 +4375.7255

==3650+4375.7256-4375=4375.7256-725

Suy ra 2 vế bằng nhau!☺

​

Ta có:

45 . 16 - 17 = 45. (15 +1) - 17

= 45 . 15 + 1.45 - 17

= 45 . 15 + (45 - 17)

= 45 . 15 + 28

vậy \(\dfrac{45.16-17}{45.15+28}=\dfrac{45.15+28}{45.15+28}=1\)

\(\dfrac{45.16-17}{28+45.15}\)

= \(\dfrac{45.\left(15+1\right)-17}{28+45.15}\)

= \(\dfrac{45.15+\left(45-17\right)}{28+45.15}\)

= \(\dfrac{45.15+27}{27+45.15}\)

= 1

~ Chúc bạn học giỏi ! ~

\(\frac{\left(456.11+912\right).37}{13.74}\)

\(=\frac{\left(456.11+456.2\right).37}{13.37.2}\)

\(=\frac{[456.\left(11+2\right).37}{13.37.2}\)

\(=\frac{456.13}{13.2}\)

\(=\frac{456}{2}=228\)

a,(56.27+56.35):62

=56x(27+35):62

=56.62:62

=56.1

=56

a)=>56.(27+32):62

=>56.62:62

=>56.1

=56

b)tự làm

c)=>45.(16+15)-17/28

=>45.31-17/28

=>1395-17/28

=19513/14

d)=>27.(45+55)/(18+2).9:2

=>2700/90

=30

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