x +2/2018x+3/2017x+4/2016= -3
ai giải giúp mik vs
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
ĐK: \(x\ge\frac{2017}{2018}\)
\(pt\Leftrightarrow2017\sqrt{2017x-2016}-2017+\sqrt{2018x-2017}-1=0\)
\(\Leftrightarrow2017\frac{2017\left(x-1\right)}{\sqrt{2017x-2016}+1}+\frac{2018\left(x-1\right)}{\sqrt{2018x-2017}+1}=0\)
\(\Leftrightarrow\left(x-1\right)\left(\frac{2017^2}{\sqrt{2017x-2016}+1}+\frac{2018}{\sqrt{2018x-2017}+1}\right)=0\)
Dễ thấy với \(x\ge\frac{2017}{2018}\Rightarrow\)\(\frac{2017^2}{\sqrt{2017x-2016}+1}+\frac{2018}{\sqrt{2018x-2017}+1}>0\)
\(\Leftrightarrow x-1=0\Leftrightarrow x=1\)
\(\text{K - 2016 = }\frac{\text{1 + ( 1 + 2 ) + ( 1 + 2 + 3 ) + ... + ( 1 + 2 + 3 + ... + 2017 )}}{\text{2017 x 1 + 2016 x 2 + 2015 x 3 + ... + 2 x 2016 + 1 x 2017}}\)
a)x2+xy-2y2=x2-xy+2xy-2y2
=x(x+2y)-y(x+2y)=(x+2y)(x-y)
câu b sai đề nha
a) x2 + xy - 2y2
=x2 + xy - y2 - y2
=(x2 - y2)+(xy-y2)
=(x-y)(x+y)+y(x-y)
=(x-y)(2y+x)
\(A=x^3+2x^2+3x\\ =x\left(x^2+2x+1\right)\\ =x\left(x+1\right)^2\\ =1999.\left(1999+1\right)=1999.2000\\ =3998000\)
\(B=x^4-2017x^3+2017x^2-2017x+2018\\ =x^4-2016x^3-x^3+2016x^2+x^2-2016x-x+2016+2\\ =x^3\left(x-2016\right)-x^3\left(x-2016\right)+x\left(x-2016\right)-\left(x-2016\right)+2\\ =\left(x-2016\right)\left(x^3+x-1\right)+2=0+2=0\)
Bạn xem lại đề câu a nhé , theo mk thì phải là 2 thì tính ms nhanh đc, 3 thì cũng giải đc nhưng ko hợp lí lắm
x^4+2018x^2−2017x+2018
=(x^4+x)+(2018x^2−2018x+2018)
=x(x^3+1)+2018(x^2−x+1)
=x(x+1)(x^2−x+1)+2018(x^2−x+1)
=(x^2−x+1)[x(x+1)+2018]
=(x^2−x+1)(x^2+x+2018)
=(x^2−x+1)(x^2+x+2018)
Ta có:
\(x^6-2017x^5+2017x^4-2017x^3+2017x^2-2017x+2017\)
\(=x^6-2016x^5-x^5+2016x^4+x^4-2016x^3-x^3+2016x^2+x^2-2016x-x+2017\)
\(=x^5\left(x-2016\right)-x^4\left(x-2016\right)+x^3\left(x-2016\right)-x^2\left(x-2016\right)+x\left(x-2016\right)-\left(x-2016\right)+1\)
Thay x = 2016 vào ta được giá trị biểu thức trên = 1
Hok tốt!
sửa đề : \(\frac{x+2}{2018}+\frac{x+3}{2017}+\frac{x+4}{2016}=-3\)
\(\Leftrightarrow\frac{x+2}{2018}+1+\frac{x+3}{2017}+1+\frac{x+4}{2016}+1=0\)
\(\Leftrightarrow\frac{x+2020}{2018}+\frac{x+2020}{2017}+\frac{x+2020}{2016}=0\)
\(\Leftrightarrow\left(x+2020\right)\left(\frac{1}{2018}+\frac{1}{2017}+\frac{1}{2016}\ne0\right)=0\Leftrightarrow x=-2020\)