a: \(=y^2+32>=32\)
Dấu = xảy ra khi y=0
b: \(=2x^2-x+2x-1\)
\(=2x^2+x-1\)
\(=2\left(x^2+\dfrac{1}{2}x-\dfrac{1}{2}\right)\)
\(=2\left(x^2+2\cdot x\cdot\dfrac{1}{4}+\dfrac{1}{16}-\dfrac{9}{16}\right)\)
\(=2\left(x+\dfrac{1}{4}\right)^2-\dfrac{9}{8}>=-\dfrac{9}{8}\)
Dấu '=' xảy ra khi x=-1/4
a) (2x+1)2+(2x+3)2-2(2x+1)(2x+3)
b) (2x-3)(2x+3)-(x-+5)2-(x-1)(x+2)
c) (24x2y3z2-12x3y2z3+36x2y2z2):(-6x2y2z2)
d) (x+2y)(x2-2xy+4y2)-(x-y)(x2+xy+y2)
e) (x3+4x2-x-4):(x+4)
f) x2(x+y)+y2(x+y)+2x2y+2xy2
g) (x+y)2+(x-y)2-2(x+y)(x-y)
h) (a+b)2-(a-b)3-2b3
i) (x-y)(x+y)(x2+y2)(x4+y4)
Mong mọi người giúp đỡ vì mai em phải nộp
a) x2+2x-y2+1
b) x2+3x-y2+3y
c) 3(x+3)-x2+9
Tìm GTLN,GTNN của:
a)A=x2+2x-3
b)B=2x2-x+1
c)C=-3x2+3x+1
d)D=-4x2+2x+3
1, Tìm GTNN
A=x2+3x-1
B=2x2+5x+2
Tìm GTNN của:
a. A=x2-4x+7
b. B=x2+8x
c. C=2x2+4x+15
Tìm x:
a) (x-20) mũ 2 -(x+1)(x+3)=-7
b) (3x+5)(4-3x)=0
c) x mũ 3 -9x=0
d)2/3x (x mũ 2 -4)=0
e) (2x+1)-x(2x+1)=0
f)(2x-1) mũ 2 -(2x+5) (2x-5) =18
g)x mũ 2 -25 =6x-9
Bài 1 : Tìm x
a) 2x ( x-5 ) - x ( 3+2x ) = 26
b) ( x-7 ) ( x+ 7) = 0
Bài 2 : Tính
a) ( x-y ) ( x^2 + xy + y^2 )
b) ( 2x-1 ) ( 2x + 1 ) ( 1 - 5x )
Bài 3 : Chứng minh
a) ( x-1 ) ( x^2 + x+1 ) = x^3-1
b) x^4 - y^4 = ( x^3 + x^2y + xy^2 + y^3 ) ( x - y )
c) x ( 2x - 3 ) - 2x. ( x+1 ) chia hết cho 5 với mọi x thuộc z
a) x2(x - 5) + 5 - x = 0; b) 3x4 - 9x3 = -9x2 + 27x;
c) x2(x + 8) + x2 = -8x; d) (x + 3)(x2 -3x + 5) = x2 + 3x.
e) 3x(x - 1) + x - 1 = 0;
f) (x - 2)(x2 + 2x + 7) + 2(x2 - 4) - 5(x - 2) = 0;
g) (2x - 1)2 - 25 = 0;
h) x3 + 27 + (x + 3)(x - 9) = 0.
i)8x3 - 50x = 0; k) 2(x + 3)-x2 - 3x = 0;
m)6x2 - 15x - (2x - 5)(2x + 5) =
Tính GTNN
a) x2-2x-1
b) 4x2+4x+5
