\(3^{8x+4}=81^{x+3}\)

\(\Rightarrow3^{8x+4}=\left(3^4\right)^{x+3}\)

\(\Rightarrow3^{8x+4}=3^{4\left(x+3\right)}\)

\(\Rightarrow8x+4=4x+12\)

\(\Rightarrow8x-4x=12-4\)

\(\Rightarrow4x=8\)

\(\Rightarrow x=\dfrac{8}{4}\)

\(\Rightarrow x=2\)

3⁸ x X = 81 x X + 3
6561 x X = 81 x X +3
6561 x X + 0 = 81 x X +3
6561 x X - 81 x X = 3 - 0
6480 x X = 3
            X = 3 : 6480 = 3/6480
            X = 1/2160
Vậy kết quả của biểu thức trên là X = 1/2160 (ko bít viết phân số trong olm :) ) Mong bạn tik cho mình

`#3107`

\(3^{8x+4}=81^{x+3}\\ \Rightarrow3^{8x+4}=\left(3^4\right)^{x+3}\\ \Rightarrow3^{8x+4}=3^{4x+12}\\ \Rightarrow8x+4=4x+12\\ \Rightarrow8x-4x=12-4\\ \Rightarrow4x=8\\ \Rightarrow x=8\div4\\ \Rightarrow x=2\\ \text{Vậy, x = 2.}\)

Lời giải:

$3^{8x+4}=81^{x+3}$

$3^{8x+4}=(3^4)^{x+3}$

$3^{8x+4}=3^{4(x+3)}$

$\Rightarrow 8x+4=4(x+3)$
$\Rightarrow 2x+1=x+3$

$\Rightarrow x=2$

\(3^{8x+4}=81^{x+3}\)

\(\Rightarrow\left(3^4\right)^{2x+1}=81^{x+3}\)

\(\Rightarrow81^{2x+1}=81^{x+3}\)

\(\Rightarrow2x+1=x+3\)

\(\Rightarrow2x-x=3-1\)

\(\Rightarrow x=2\)

\(3^{8x+4}=81^{x+3}\)

\(3^{8x+4}=\left(3^4\right)^{x+3}\)

\(3^{8x+4}=3^{4x+12}\)

\(\Rightarrow8x+4=4x+12\)

\(\Rightarrow8x-4x=12-4\)

\(\Rightarrow4x=8\Rightarrow x=2\)

2

  3^{8.x + 4} = 81^{x + 3}

  3^{8.x + 4} = (3⁴)^{x + 3}

  3^{8.x + 4} = 3^{4.x + 12}

  8.x + 4 = 4.x + 12

8.x - 4.x = 12 - 4

        4.x = 8

           x = 8 : 4

           x = 2

3⁵ˣ⁺⁴ = 81ˣ⁺³

3⁵ˣ⁺⁴ = (3⁴)ˣ⁺³

3⁵ˣ⁺⁴ = 3⁴ˣ⁺¹²

5x + 4 = 4x +12

5x - 4x =12 - 4

x = 8

a, \(x^4-6x^3+11x^2-6x+1=0\)

\(\Rightarrow\left(x^2-3x+1\right)^2=0\)

\(\Rightarrow x^2-3x+1=0\)

\(\Rightarrow x=\frac{\pm\sqrt{5}+3}{2}\)

Chúc bạn học tốt

\(x^4-\left(6x^2-2x^2\right)+\left(9x^2-6x+1\right)=0\)

\(x^4-2x^2\left(3x-1\right)+\left(3x-1\right)^2=0\)

\(\left(x^2-3x+1\right)^2=0\)

tự làm

B) \(\left(6x^4-18x^3\right)+\left(13x^{^3}-39x^2\right)+\left(x-3x\right)-\left(2x-6\right)=0\)

\(6x^3\left(x-3\right)+13x^2\left(x-3\right)+x\left(x-3\right)-2\left(x-3\right)=0\)

\(\left(x-3\right)\left(6x^3+13x^2-2\right)=0\)

\(\left(x-3\right)\left(6x^3+12x^2+x^2+2x-x-2\right)\)

\(\left(x-3\right)\left\{6x^2\left(x+2\right)+x\left(x+2\right)-\left(x+2\right)\right\}\)

\(\left(x-3\right)\left(x+2\right)\left(6x^2-x-1\right)\)

  \(\left(x-3\right)\left(x+2\right)\left(6x^2-3x+2x-1\right)\)

\(\left(x-3\right)\left(x+2\right)\left(3x\left(2x-1\right)+\left(2x-1\right)\right)\)

\(\left(x-3\right)\left(x+2\right)\left(2x-1\right)\left(3x+1\right)=0\)

câu C nghĩ đã

8X-5(5X^2-1)^2=-4

a, \(x^4-6x^3+11x^2-6x+1=0\)

=> \(x^4-6x^3+9x^2+2x^2-6x+1=0\)

=> \(x^2+3x+1=0\)

=> \(\Delta\) =\(b^2-4c\)

=\(3^2.4=5\)

Nên \(\sqrt{\Delta}=5\)

x= \(\dfrac{-b+\sqrt{\Delta}}{2a}=\dfrac{-3+\sqrt{5}}{2}\)

hoặc x= \(\dfrac{b+\sqrt{\Delta}}{2a}=\dfrac{3+\sqrt{5}}{2}\)

Đáp án câu a.

https://giaibaitapvenha.blogspot.com/2017/12/toan-lop-8-ai-so_27.html

d,Sửa đề

\(-x^3+6x^2-12x+8\)

\(=-\left(x^3-6x^2+12x-8\right)\)

\(=-\left(x^3-3.x^2.2+3.x.2^2-2^3\right)\)

\(=-\left(x-2\right)^3\)

\(e,27x^3+81x^2+81x+27\)

\(=27\left(x^3+3x^2+3x+1\right)\)

\(=27\left(x+1\right)^3\)