Tìm x, biết:
a. (2x−3)2−4=0\left(2x-3\right)^2-4=0(2x−3)2−4=0
b.x2−2x=0x^2-2x=0x2−2x=0
c.(2x−1)2+(x+3)2−5(x+7)(x−7)=0\left(2x-1\right)^2+\left(x+3\right)^2-5\left(x+7\right)\left(x-7\right)=0(2x−1)2+(x+3)2−5(x+7)(x−7)=0
a, (2x−3)2−4=0\left(2x-3\right)^2-4=0(2x−3)2−4=0
<=> (2x−3)2=4\left(2x-3\right)^2=4(2x−3)2=4
<=> [2x−3=22x−3=−2⇔[x=52x=12\left[{}\begin{matrix}2x-3=2\\2x-3=-2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{2}\\x=\dfrac{1}{2}\end{matrix}\right.[2x−3=22x−3=−2⇔⎣⎢⎡x=25x=21
Vậy-..
b, x2−2x=0x^2-2x=0x2−2x=0
⇔x(x−2)=0⇔[x=0x−2=0⇒x=2\Leftrightarrow x\left(x-2\right)=0\Leftrightarrow\left[{}\begin{matrix}x=0\\x-2=0\Rightarrow x=2\end{matrix}\right.⇔x(x−2)=0⇔[x=0x−2=0⇒x=2
Vậy=
c, (2x−1)2+(x+3)2−5(x+7)(x−7)=0\left(2x-1\right)^2+\left(x+3\right)^2-5\left(x+7\right)\left(x-7\right)=0(2x−1)2+(x+3)2−5(x+7)(x−7)=0
⇔4x2−4x+1+x2+6x+9−5x2+245=0\Leftrightarrow4x^2-4x+1+x^2+6x+9-5x^2+245=0⇔4x2−4x+1+x2+6x+9−5x2+245=0
⇔2x=−255⇔x=−2552\Leftrightarrow2x=-255\Leftrightarrow x=-\dfrac{255}{2}⇔2x=−255⇔x=−2255
Vậy-...
rút gọn rồi tính giá trị biểu thức:
x3−9x2+27x−27x^3-9x^2+27x-27x3−9x2+27x−27 tại x = 5
Tim GTLN cua bieu thuc
a)x2−20x+101x^2-20x+101x2−20x+101
b) 4x2+4x+24x^2+4x+24x2+4x+2
c) 11−10x+x211-10x+x^211−10x+x2
Giúp mk với mk đg cần gấp
Cho x+y+z=0. CMR: 2(x5+y5+z5)= 5xyz(x2+y2+z2)
Bài 1:
Cho a2+b2+c2=ab+bc+ca^{a^2+b^2+c^2=ab+bc+ca}a2+b2+c2=ab+bc+ca
Cmr : a=b=ca=b=ca=b=c
Bài 2 :
Tìm a , b , c thỏa mãn
a2−2a+b2+4b+4c2−4c+6=0a^2-2a+b^2+4b+4c^2-4c+6=0a2−2a+b2+4b+4c2−4c+6=0
Bài 1
Cho a2+b2+c2+3=2(a+b+c)a^2+b^2+c^2+3=2\left(a+b+c\right)a2+b2+c2+3=2(a+b+c)
CMR a=b=c=1a=b=c=1a=b=c=1
Bài 2
Cho (a+b+c)2=3(ab+ac+bc)\left(a+b+c\right)^2=3\left(ab+ac+bc\right)(a+b+c)2=3(ab+ac+bc)
Cmr a=b=ca=b=ca=b=c
Tìm giá trị lớn nhất của biểu thức:
N= x - x^2
Tìm số nguyên x,y biết y2+2xy-7x-12=0
Cho x+y=a
x2+y2=bx^2+y^2=bx2+y2=b
x3+y3=cx^3+y^3=cx3+y3=c
CM a3+2c=3aba^3+2c=3aba3+2c=3ab
(x-3)^2-4=0
14x - 14y - x2 + 2xy - y2 =
