(14,78-a)/(2,87+a)=4/1

14,78+2,87=17,65

Tổng số phần bằng nhau là 4+1=5

Mỗi phần có giá trị bằng 17,65/5=3,53

=>2,87+a=3,53

=>a=0,66.

a) A= 5⁴ . 3⁴- (15²-1).(15²+1)

      =(5.3)⁴-15⁴-1

      =15⁴-15⁴-1

      =-1

a) A= 5⁴.3⁴ -(15²-1).(15²+1)

      =(5.3)⁴ - (15⁴-1)

      = 15⁴ - 15⁴ +1

      =   1

bạn nào trả lời cho mình đi

\(C=50^2-49^2+48^2-47^2+...+2^2-1^2\)

\(=1+2+3+4+...+49+50\)

\(=51\cdot25=1275\)

1. 

$=153^2+2.47.153+47^2=(153+47)^2=200^2=40000$

2.

$=1,24^2-2.1,24.0,24+0,24^2=(1,24-0,24)^2=1^2=1$

3. Không phù hợp để tính nhanh 

4. 

$=15^8-(15^8-1)=1$

5.

$=(1^2-2^2)+(3^2-4^2)+(5^2-6^2)+...+(2019^2-2020^2)$

$=(1-2)(1+2)+(3-4)(3+4)+(5-6)(5+6)+...+(2019-2020)(2019+2020)$

$=(-1)(1+2)+(-1)(3+4)+(-1)(5+6)+....+(-1)(2019+2020)$

$=(-1)(1+2+3+4+....+2019+2020)=(-1).2020(2020+1):2=-2041210$

6:

\(\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)....\left(2^{2020}+1\right)+1\\ =1.\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)....\left(2^{2020}+1\right)+1\\ =\left(2-1\right)\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)....\left(2^{2020}+1\right)+1\\ =\left(2^2-1\right)\left(2^2+1\right)\left(2^4+1\right)....\left(2^{2020}+1\right)+1\\ =\left(2^4-1\right)\left(2^4+1\right)....\left(2^{2020}+1\right)+1\\ =\left(2^8-1\right)....\left(2^{2020}+1\right)+1\\ =\left(2^{2020}-1\right)\left(2^{2020}+1\right)+1\\ =2^{4040}-1+1=2^{4040}\)

trên đầu bài là giấu phẩy hay giấu nhân thế

\(a,2^2=4,2^3=8,2^4=16,2^5=32,2^6=64,2^7=128,2^8=256,2^9=512,2^{10}=1024\)

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

\(c,4^2=16,4^3=64,4^4=256\)

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

a: \(2^2=4\)

\(2^3=8\)

\(2^4=16\)

\(2^5=32\)

\(2^6=64\)

\(2^7=128\)

\(2^8=256\)

\(2^9=512\)

\(2^{10}=1024\)

b: \(3^2=9\)

\(3^3=27\)

\(3^4=81\)

\(3^5=243\)

c: \(4^2=64\)

\(4^3=256\)

\(4^4=1024\)

d: \(5^2=25\)

\(5^3=125\)

\(5^4=625\)

\(=\left(1-2\right)\left(1+2\right)+\left(3-4\right)\left(3+4\right)+...+\left(2003-2004\right)\left(2003+2004\right)+2005^2\\ =-\left(1+2\right)-\left(3+4\right)-...-\left(2003+2004\right)+2005^2\\ =-\left(1+2+3+...+2003+2004\right)+2005^2\\ =-\dfrac{\left(2004+1\right)\cdot2004}{2}+2005^2\\ =2011015\)

a) \(=\left(127+73\right)^2=200^2=40000\)

b) \(=18^8-\left(18^8-1\right)=1\)

c) \(=\left(100+99\right)\left(100-99\right)+\left(98+97\right)\left(98-97\right)+...+\left(2+1\right)\left(2-1\right)\)

\(=100+99+98+97+...+2+1=5050\)

d) biến đổi thành \(20^2-19^2+18^2-17^2+..+2^2-1^2\)

rồi giải ra như trên

 a)\(...A=\dfrac{2^{50+1}-1}{2-1}=2^{51}-1\)

b) \(...\Rightarrow B=\dfrac{3^{80+1}-1}{3-1}=\dfrac{3^{81}-1}{2}\)

c) \(...\Rightarrow C+1=1+4+4^2+4^3+...+4^{49}\)

\(\Rightarrow C+1=\dfrac{4^{49+1}-1}{4-1}=\dfrac{4^{50}-1}{3}\)

\(\Rightarrow C=\dfrac{4^{50}-1}{3}-1=\dfrac{4^{50}-4}{3}=\dfrac{4\left(4^{49}-1\right)}{3}\)

Tương tự câu d,e,f bạn tự làm nhé

https://olm.vn/cau-hoi/a-cho-a12211216211002-ctr-a12-b-cho-p122132142120232-ctr-p-khong-la-so-tu-nhien-c-cho-c132152172120211.8293222842881

Cô làm rồi em nhá