tìm số nguyên x biết: a) (x-8)^3=-64 b) ( 2x -1 )^3=-27 c) x^2 -3x =0 d) ( x+1) +(x+2)+(x+3) +...+(x+100)=5750

$\text{Đáp án+Giải thích các bước giải:}$

a)$(x-8)^{3}$=-64

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

$\text{x-8=-4}$

  $\text{x=-4+8=4}$

b)$(2x-1)^{3}$$\text{=-27}$

$(2x-1)^{3}$=-$3^{3}$ 

$\text{2x-1=-3}$

$\text{2x=-3+1=-2}$

$\text{x=-2:2=-1}$

$\text{c)}$$x^{2}$$\text{-3x=0}$

$\text{x.x-3.x=0}$

$\text{x.(x-3)=0}$

$\Rightarrow$$\text{x=0;x-3=0}$ `\text{hoặc x=0 ;x=3 }`

$\text{d)( x+1) +(x+2)+(x+3) +...+(x+100)=5750}$

$\text{(x+x+...+x)+(1+2+3+...+100)=5750}$

$\text{(x.100)+(1+100).100:2=5750}$

$\text{(x.100)+5050=5750}$

$\text{x.100=5750-5050}$

$\text{x.100=700}$

$\text{x=700:100=7}$

$\textit{#Kakashi hatake}$

$\textit{Chúc bạn học tốt.}$