Ta có:\(5^n.2,5-30.5^n-6.5^n-1=5^n.\left(25-30-6\right)-1=5^n.\left(-11\right)-1\)-1

\(=25.5^{n-3}+5^n-6.5^{n-1}\)

\(=5^{n-3+2}+5^n-6.5^{n-1}\)

\(=5^{n-1}+5^n-6.5^{n-1}\)

\(=5^{n-1}\left(1-6\right)+5^n=-5.5^{n-1}+5^n=-5^{n-1+1}+5^n=-5^n+5^n=0\)

Viết dễ hiểu vào

minh moi hok lop 6

a) 10^{n + 1} - 6.10ⁿ

= 10ⁿ . 10 - 6 . 10ⁿ

= 10ⁿ . (10 - 6)

= 10ⁿ . 4

b) 2^{n + 3} + 2^{n + 2} - 2^{n + 1} + 2ⁿ

= 2ⁿ . 2³ + 2ⁿ . 2² - 2ⁿ . 2 + 2ⁿ . 1

= 2ⁿ . (8 + 4 - 2 + 1)

= 2ⁿ . 11

a) \(10^n+1-6\cdot10^n=\left(1-6\right)10^n+1=-5\cdot10^n+1\)

b)  \(90\cdot10^n-10^2-2+10^n+1=\left(90-1+1\right)\cdot10^n-2+1=90\cdot10^n-1\)

c)  \(2,5\cdot56^n-3=\frac{5}{2}\cdot56^n-3\)

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\(d,2,5.5^{n-3}.2.5+5^n-6.5^{n-1}=5.5.5^{n-3}+5^n-6.5^{n-1}=5^2.5^{n-3}+5^n-6.5^{n-1}\)

  \(=5^{n-3+2}+5^n-6.5^{n-1}=5^{n-1}\left(1+5-6\right)=5^{n-1}.0=0\)

a, \(10^{n+1}-6.10^n=10^n\left(10-6\right)=4.10^n\)

b. \(2^{n+3}+2^{n+2}-2^{n+1}+2^n=2^n\left(2^3+2^2-2+1\right)=2^n\left(8+4-2+1\right)=11.2^n\)

Mình cho bạn tự làm câu d  mà không làm thôi làm cho vậy