=221-16+2-1

=205+1

=206

vậy nhó

=221-16+2-1=206

27.75 + 25.27 - 150

= 27.(75+25) - 150

= 27.100 - 150

= 27.10.10 - 15.10

= 270.10 - 15.10

= 10.(270-15)

= 10.255

= 2550

cảm ơn b

5.3² - 32:4²

= 5.9 - 2⁵:(2²)²

= 45 - 2⁵:2⁴

= 45 - 2

= 43

43

2 . 5² + 3 : 71⁰ - 54 : 3³

= 2.25 + 3:1 - 54: 27

= 50 + 3 - 2

= 51

51

2^2x+1 + 4^x+3 = 264

2^2x+1 + 2^2x+3.2 = 264

2^2x+1 + 2^2x+6 =264

 2^2x.2 + 2^2x.2⁶ = 264

2^2x(2+64) = 264

2^2x.66 = 264

2^2x = 4

2^2x = 2²

2x=2

x=2:2

x=1

2^x + 2^{x + 3} = 144

2^x + 2^x . 2³ = 144

2^x . 1 + 2^x . 2³ = 144

2^x ( 1 + 8 ) = 144

2^x . 9 = 144

2^x = 16

2^x = 2⁴

Vậy x = 4

2^x + 2^x+3 = 144

2^x + 2^x.2³ = 144

2^x + 2^x.8 = 144

2^x.(8+1) = 144

2^x.9 = 144

2^x = 144 : 9

2^x = 16

2^x = 2⁴

x = 4

Bài 1:

\(\text{Ư}\left(12\right)=\left\{1;2;3;4;6;12\right\}\)

\(Ư\left(25\right)=\left\{1;5;25\right\}\)

\(Ư\left(40\right)=\left\{1;2;4;5;8;10;20;40\right\}\)

\(Ư\left(50\right)=\left\{1;2;5;10;25;50\right\}\)

Bài 2:

\(B\left(13\right)=\left\{0;13;26;...\right\}\)

\(B\left(16\right)=\left\{0;16;32;...\right\}\)

\(B\left(20\right)=\left\{0;20;40;...\right\}\)

Bài 1 Ước của các số là:

Ư(12)={-1;-2;-3;-4;-6;-12;1;2;3;4;6;12}

Ư(25)={-1;-5;-25;1;5;25}

Ư(40)={-1;-2;-4;-5;-8;-10;-20;-40;1;2;4;5;8;10;20;40}

Ư(50)={1;-1;2;-2;5;-5;10;-10;25;-25;50;-50} 

Bài 2 Bội của các số là

B(13)={13;26}

B(16)={16;32}

B(20)={20;40}

`x^2:2=8`

`x^2=8.2=16`

`x^2=4^2`

`x=4`

X² ÷ 2 = 8

X²        = 8 x 2

X²         = 16

X²          = 4²

⇒ x = 4