Tìm x biết :
\(\left(2x-1\right)^3+\left(3x+2\right)^3-\left(5x+1\right)^3=0\)
MẤY BẠN GIÚP MK VS Ạ AI NHANH MK VOTE NHA
RÚT GỌN BIỂU THỨC SAU
\(\left(x-2\right)^3-x\left(x+1\right)\left(x-1\right)+6x\left(x-3\right)\)
MẤY BẠN GIÚP MK VS Ạ AI NHANH MK VOTE NHA
\(=x^6-6x^4+12x^2-8-x^3+x+6x^2-18x\\ =x^6-6x^4-x^3+18x^2-17x-8\)
RÚT GỌN BIỂU THỨC SAU
\(\left(x+\dfrac{1}{3}x+\dfrac{1}{9}\right)\left(x-\dfrac{1}{3}\right)-\left(x-\dfrac{1}{3}\right)^2\)
MẤY BẠN GIÚP MK VS Ạ AI NHANH MK VOTE NHA
\(=\left(x-\dfrac{1}{3}\right)\left(\dfrac{4}{3}x+\dfrac{1}{9}-x+\dfrac{1}{3}\right)\\ =\left(x-\dfrac{1}{3}\right)\left(\dfrac{1}{3}x+\dfrac{4}{9}\right)\\ =\dfrac{1}{3}x^2+\dfrac{4}{9}x-\dfrac{1}{9}x-\dfrac{4}{27}\\ =\dfrac{1}{3}x^2+\dfrac{1}{3}x-\dfrac{4}{27}\)
Cho \(2x^2+y^2+2x-2xy+5-4y=0\)
Tính S= \(\left(x+2^{ }\right)^2+\left(y-1\right)^2\)
MẤY BẠN GIÚP MK VS Ạ AI NHANH MK VOTE NHA
\(2x^2+y^2+2x-2xy+5-4y=0\)
\(\Leftrightarrow\left[y^2-2y\left(x+2\right)+\left(x+2\right)^2\right]+\left(x^2-2x+1\right)=0\)
\(\Leftrightarrow\left(y-x-2\right)^2+\left(x-1\right)^2=0\)
\(\Leftrightarrow\left[{}\begin{matrix}y-x-2=0\\x-1=0\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x=1\\y=3\end{matrix}\right.\)
\(S=\left(x+2\right)^2+\left(y-1\right)^2=\left(1+2\right)^2+\left(3-1\right)^2\)
\(=3^2+2^2=13\)
Tìm x biết :
(2x−1)3+(3x+2)3−(5x+1)3=0
MẤY BẠN GIÚP MK VS Ạ AI NHANH MK VOTE NHA
Rút gọn các biểu thức sau:
a/\(\left(x+\dfrac{1}{3}x+\dfrac{1}{9}\right)\left(x-\dfrac{1}{3}\right)-\left(x-\dfrac{1}{3^{ }}\right)^2\)
b/\(\left(x_{ }^2-2\right)^3-x\left(x+1\right)\left(x-1\right)+x\left(x-3\right)\)
MẤY BẠN GIÚP MK VS Ạ AI NHANH MK VOTE NHA
a) \(=x^3-\dfrac{1}{27}-x^2+\dfrac{2}{3}x-\dfrac{1}{9}=x^3-x^2+\dfrac{2}{3}x-\dfrac{2}{27}\)
b) \(=x^6-6x^4+12x^2-8-x^3+x+x^2-3x=x^6-6x^4-x^3+13x^2-2x-8\)
tìm x biết
a) \(\left(x-2\right)^3\left(x-3\right)\left(x^2+3x+9\right)+6\left(x+1\right)^2=49\)
b)\(\left(x+2\right)\left(x^2-2x+4\right)-x\left(x^2+2\right)=15\)
c)\(\left(x+3\right)^3-x\left(3x+1\right)^2+\left(2x+1\right)\left(4x^2-2x+1\right)=28\)
d)\(\left(x^2-1\right)^3-\left(x^4+x^2+1\right)\left(x^2-1\right)=0\)
Giúp mk vs đc k ạ mk đg cần gấp
\(b,\left(x+2\right)\left(x^2-2x+4\right)-x\left(x^2+2\right)=15\)
\(\Leftrightarrow x^3+8-x^3-2x=15\)
\(\Leftrightarrow-2x=15-8=7\)
\(\Leftrightarrow x=\frac{-7}{2}\)
Vậy \(x=\frac{-7}{2}\)
Tìm GTNN của
a/A=\(a^2+5b^2-4ab-2b+5\)
b/B=\(\left(x-y\right)^2+\left(y-3^{ }\right)^2+\left(x-3\right)^2+2021\)
Ai giúp mk vs ạ ai nhanh mk tick nha :3
b: \(B\ge2021\forall x,y\)
Dấu '=' xảy ra khi x=y=3
Cho M= \(\left(x-a\right)\left(x-b\right)+\left(x-b\right)\left(x-c\right)+x^2\)
M the a,b,c biết \(x=\dfrac{1}{2}a+\dfrac{1}{2}b+\dfrac{1}{2}c\)
Ai giups mk vs ai nhanh mk sẽ vote nha
Từ x=\(\dfrac{1}{2}\)a+\(\dfrac{1}{2}\)b+\(\dfrac{1}{2}\)c=\(\dfrac{1}{2}\).(a+b+c)\(\Rightarrow\)2x=(a+b+c)
M=(x-a)(x-b)+(x-b)(x-c)+(x-c)(x-a)+x\(^2\)
= x\(^2\)-xb-ax+ab+x\(^2\)-xc-bx+bc+x\(^2\)-ax-cx+ac+x\(^2\)
= 4x\(^2\)-2ac-2bx-2cx+ab+bc+ac
= 4x\(^2\)-2x(a+b+c)+ab+bc+ca
Thay 2x=a+b+c,ta được:
M= 4x\(^2\)-2x.2c+ab+bc+ca
M= 4x\(^2\)-4x\(^2\)+ab+bc+ca
M= ab+bc+ca
Tìm x biết:
\(a.3x^2-3x\left(x-2\right)=36\)
\(b.x\left(2x-1\right)\left(x+5\right)-\left(2x^2+1\right)\left(x+4,5\right)=3,5\)
\(c.\left(3x^2-x+1\right)\left(x-1\right)+x^2\left(4-3x\right)=\frac{5}{2}\)
Giúp mk vs ạ <3 <3
a)\(\Leftrightarrow3x^2-3x^2+6x=36\Leftrightarrow6x=36\Leftrightarrow x=6\)