1).15,3-21,5-3.1,5 = -10.7

2).2(4  ^2-2.4,1)+1,25:5 = 0.300370048 ( cái nài mik bấm máy ra vậy nếu sai thì bảo mik nha )

a, 

\(\begin{array}{l}15,3 - 21,5 - 3.1,5\\ = 15,3 - 21,5 - 4,5\\ = 15,3 - \left( {21,5 + 4,5} \right)\\ = 15,3 - 26\\ =  - \left( {26 - 15,3} \right)\\ =  - 10,7\end{array}\)

b, 

\(\begin{array}{l}2.\left( {{4^2} - 2.4,1} \right) + 1,25:5\\ = 2.\left( {16 - 8,2} \right) + 0,25\\ = 2.7,8 + 0,25\\ = 15,6 + 0,25\\ = 15,85\end{array}\)

a, 15 , 3 − 21 , 5 − 3.1 , 5 = 15 , 3 − 21 , 5 − 4 , 5 = 15 , 3 − ( 21 , 5 + 4 , 5 ) = 15 , 3 − 26 = − ( 26 − 15 , 3 ) = − 10 , 7 b, 2. ( 4 2 − 2.4 , 1 ) + 1 , 25 : 5 = 2. ( 16 − 8 , 2 ) + 0 , 25 = 2.7 , 8 + 0 , 25 = 15 , 6 + 0 , 25 = 15 , 85

a) \(1,25^2-0,5^2+3,25^3\)

\(=\left(\frac{5}{4}\right)^2-\left(\frac{1}{2}\right)^2+\left(\frac{13}{4}\right)^3\)

\(=\frac{25}{16}-\frac{1}{4}+\frac{2197}{64}\)

\(=\frac{2281}{64}\)

b) \(1,2+2,4^2-\left(3\frac{1}{2}\right)^2\)

\(=\frac{6}{5}+\left(\frac{12}{5}\right)^2-\left(\frac{7}{2}\right)^2\)

\(=\frac{6}{5}+\frac{144}{25}-\frac{49}{4}\)

\(=\frac{-529}{100}\)

a) 2³ = 8; 2⁴ = 16; 2⁵ = 32; 2⁶ = 64; 2⁷ = 128; 2⁸ = 256; 2⁹ = 512; 2¹⁰ = 1024

b) 3² = 9; 3³ = 27; 3⁴ = 81; 3⁵ = 243

c) 4² = 16; 4³ = 64; 4⁴ = 256

d) 5² = 25; 5³ = 125; 5⁴ = 625

c) 6² = 36; 6³ = 216; 6⁴ = 1296

a) 2³ = 8; 2⁴ = 16; 2⁵ = 32; 2⁶ = 64; 2⁷ = 128; 2⁸ = 256; 2⁹ = 512; 2¹⁰ = 1024

b) 3² = 9; 3³ = 27; 3⁴ = 81; 3⁵ = 243

c) 4² = 16; 4³ = 64; 4⁴ = 256

d) 5² = 25; 5³ = 125; 5⁴ = 625

e) 6² = 36; 6³ = 216; 6⁴ = 1296

HT

4 mũ 3- 2×(4- 2 mũ3)

A = 2^3 + 2^4+ 2^5+ 2^6 + 2^7 + ... + 2^90 

2A = 2^4 + 2^5 + 2^6 + 2^7 + 2^8 + .... + 2^90 + 2^100

2A - A = ( 2^4 + 2^5 + 2^6 + 2^7 + 2^8 + .... + 2^90 + 2^100 ) - (  2^3 + 2^4+ 2^5+ 2^6 + 2^7 + ... + 2^90 ) 

A = 2^100 - 2^3 

B = 1 + 5 + 5^2 + 5^3 + 5^4 + .... + 5^50 

5B = 5 + 5^2 + 5^3 + 5^4 + 5^5 + .... + 5^50 + 5^51 

5B - B = ( 5 + 5^2 + 5^3 + 5^4 + 5^5 + .... + 5^50 + 5^51 ) - ( 1 + 5 + 5^2 + 5^3 + 5^4 + .... + 5^50 )

4B = 5^51 - 1 

B = 5^51 - 1 / 4

5^3.52+5^3.7-5^3

=5^3(52+7-1)

=5^3.58

=7250

giúp mình đi

giúp mình đi 

2² = 4; 2³ = 8; 2⁴ = 16; 2⁵ = 32; 2⁶ = 64

2⁷ = 128; 2⁸ = 256; 2⁹ = 512; 2¹⁰ = 1024

3² = 9;  3³ = 27;  3⁴ = 81;  3⁵ = 243

4² = 16;  4³ = 64;  4⁴ = 256

5² = 25;  5³ = 125; 5⁴ = 625

\(2^2=4;2^3=8;2^4=16;2^5=32;2^6=64\)

\(2^7=128;2^8=256;2^9=512;2^{10}=1024\)

\(3^2=9;3^3=27;3^4=81;3^5=243\)

\(4^2=16;4^3=64;4^4=256\)

\(5^2=25;5^3=125;5^4=625\)

4 mũ 3 -2 mũ 3 và 2+(42 mũ3

Hai bài trên áp dụng công thức với khoảng cách là 2.

Ta có:

\(D=1+2^1+2^2+2^3+.....+2^{150}\)

\(\Rightarrow2D-D=\left(2+2^2+2^3+2^4+.....+2^{151}\right)-\left(1+2+2^2+2^3+....+2^{150}\right)\)

\(\Rightarrow D=2^{151}-1\)

\(E=1+4^1+4^2+....+4^{400}\)

\(\Rightarrow4E-E=\left(4+4^2+4^3+....+4^{401}\right)-\left(1+4^1+4^2+....+4^{400}\right)\)

\(\Rightarrow E\left(4-1\right)=4^{401}-1\Leftrightarrow E=\frac{4^{401}-1}{4-1}\)

Các câu còn lại làm tương tự

Bài 8:

a: \(\left(\dfrac{2}{5}+\dfrac{3}{4}\right)^2=\left(\dfrac{8+15}{20}\right)^2=\left(\dfrac{23}{20}\right)^2=\dfrac{529}{400}\)

b: \(\left(\dfrac{5}{4}-\dfrac{1}{6}\right)^2=\left(\dfrac{15}{12}-\dfrac{2}{12}\right)^2=\left(\dfrac{13}{12}\right)^2=\dfrac{169}{144}\)