thu gon bieu thuc M= 2 ^n-1+2.2^n+3-8.2^n-4-16.2^n
ta dc ket qua
( may ban giup mink voi nha)
Thu ngọn biểu thức M = 2^n-1 + 2.2^n+3 - 8.2^n-4 - 16.2^n
Ta được kết quả là ...
Sai thì thôi nha
Từ M ta có:
\(M=2^n-2.2^n+8+2.2^n-16-16.2^n\)
\(M=2^n.\left(-2+2+2-16\right)+8-16\)
M=\(2^n.\left(-14\right)-8\)
Vậy thu gọn M ta được....
Thu gọn các biểu thức sau:
a) \(A=2^{n-1}+2.2^{n+3}-8.2^{n-4}-16.2^n\)
b) \(B=\left(3^{n+1}-2.2^n\right)\left(3^{n+1}+2.2^n\right)-3^{2n+2}+\left(8.2^{n-2}\right)^2\)
a) \(A=2^{n-1}+2.2^{n+3}-8.2^{n-4}-16.2^n\)
\(=2^{n-1}+2^{n+3+1}-2^{n-4+3}-2^{n+4}\)
\(=2^{n-1}+2^{n+4}-2^{n-1}-2^{n+4}\)
\(=0\)
b) \(B=\left(3^{n+1}-2.2^n\right)\left(3^{n+1}+2.2^n\right)-3^{2n+2}+\left(8.2^{n-2}\right)^2\)
\(=\left(3^{n+1}-2^{n+1}\right)\left(3^{n+1}-2^{n+1}\right)-3^{2n+2}+2^{2n+2}\)
\(=3^{2n+2}-2^{2n+2}-3^{2n+2}+2^{2n+2}\)
\(=0\)
Thu gọn :
a) \(2^{n-1}+2.2^{n+3}-8.2^{n-4}-16.2^n\)
b) \(\left(3^{n+1}-2.2^n\right)\left(3^{n+1}+2.2^n\right)-3^{2n+2}+\left(8.2^{n-2}\right)\)
Thu gọn A=2n-1+2.2n+3-8.2n-4-16.2n
\(A=2^{n-1}+2^{n+4}-2^3\cdot2^{n-4}-2^4\cdot2^n\)
\(A=2^{n-1}+2^{n+4}-2^{n-1}-2^{n+4}\)
\(A=0\)
Thu gọn các biểu thức sau:
a) \(A=2^{n-1}+2.2^{n+3}-8.2^{n-4}-16.2^n\)
b) \(B=\left(3^{n+1}-2.2^n\right)\left(3^{n+1}+2.2^n\right)-3^{2n+2}+\left(8.2^{n-2}\right)^2\)
HELP!!!!
a,
\(A=2^{n-1}+2.2^{n+3}-8.2^{n-4}-16.2^n\)
\(=2^{n-1}+2^{n+3+1}-2^{n-4+3}-2^{n+4}\)
\(=2.2^{n-1}+2.2^{n+4}=2^n+2^{n+5}\)
b,
\(B=\left(3^{n+1}-2.2^n\right)\left(3^{n+1}+2.2^n\right)-3^{2n+2}+\left(8.2^{n-2}\right)^2\)
\(=\left(3^{n+1}\right)^2-\left(2.2^n\right)^2-\left(3^{n+1}\right)^2+\left(2^{n-2+3}\right)^2\)
\(=-2^{n+1}+2^{n+1}=0\)
Rút gọn phân thức \(M=2^{n-1}+2.2^{n-3}-8.2^{n-4}-16.2^n\)
Ai giup m voi: Thu gon roi tinh bieu thuc sau:
C= x^5 - 5x^4 + 5x^3 - 5x^2 + 5x -1 voi x=4
Dễ thấy 5=4+1=x+1
Thay vào C,ta có:
\(C=x^5-\left(x+1\right)x^4+\left(x+1\right)x^3-\left(x+1\right)x^2+\left(x+1\right)x-1\)
\(=x^5-x^5-x^4+x^4+x^3-x^3-x^2+x^2+x-1=x-1=4-1=3\)
a/ tìm giá trị nhỏ nhất của đa thức P = (x-1)(2x+3)
b/ rút gọn M = 2n-1+ 2.2n+3- 8.2n-4- 16.2n
P = (x-1)(2x+3)
=> P=2x2+3x-2x-3
=> P=2x2+x-3
=> P=\(2x^2+x+\dfrac{1}{8}-\dfrac{25}{8}\)
=> P=2\(\left(x^2+\dfrac{1}{2}x+\dfrac{1}{16}\right)-\dfrac{25}{8}\)
=> P=\(2\left(x+\dfrac{1}{4}\right)^2-\dfrac{25}{8}\)
=> min P =\(\dfrac{-25}{8}\) khi \(x+\dfrac{1}{4}=0\Rightarrow x=-\dfrac{1}{4}\)
2015 ×(2015-1)×(2015-2)×(2015-3)×...(2015-k)
Voi k€ N va tich trên co dung 2016 thua so.
May ban giup mink nhanh chóng thi mink tick cho nha.
kết quả phép tính này =0 nha bạn
k mik nha.