a, 4.(x+2)=2.(x-1)+4 b,(x+1)+(2x+2)+(3x+3)+(4x+4)=80
làm phép chia :
a) (x^4 -2x^3 + 2x -1) : (x^2 - 1)
b) (x^3 -8) : (x^2 + 2x +4)
c) (x^6 - 2x^5 + 2x^4 + 6x^3 - 4x^2)n: 6x^2
d) (-2x^5 + 3x^2 - 4x^3) :2x^2
e) (15x^3 - 10x^2 + x - 2) : (x - 2)
f) (2x^4 - 3x^3 - 3x^2 + 6x - 2) : (x^2 - 2)
b: =x-2
d: \(=-x^3+\dfrac{3}{2}-2x\)
Bài 1 : Tìm thương Q và dư R sao cho A= B.Q+R biết ;
a) A = \(x^4+3x^3+2x^2-x-4\) và B = \(x^2-2x+3\)
b) A = \(2x^3-3x^2+6x-4\) và B = \(x^2-x+3\)
c) A = \(2x^4+x^3+3x^2+4x+9\) và B = \(x^2+1\)
d) A = \(2x^3-11x^2+19x-6\) và B = \(x^2-3x+1\)
c) A= \(2x^4-x^3-x^2-x+1\) và B = \(x^2+1\)
Bài 1:
a) x (\(x^2\) + 2) + 2x\((1-\dfrac{1}{2}x^2)=4\)
b) (2x)\(^2\) (x – 1) + x(\(x^2\) + 4x) = 40
c) 3x(x – 2) – 3(\(x^2\) – 3) = 8
d) 2\(x^2\)(4\(x^3\) + 2x) + (\(x^2\) – 2)(- 2x)\(^3\) = 20
Bài 2:
P = 3x(\(\dfrac{2}{3}\)\(x^2\) − \(3x^4)\) + (3x)\(^2\) (\(x^3\) – 1) + (- 2x + 9)\(x^2\) - 12
Bài 2:
Ta có: \(P=3x\left(\dfrac{2}{3}x^2-3x^4\right)+9x^2\left(x^3-1\right)+x^2\left(-2x+9\right)-12\)
\(=2x^3-9x^5+9x^5-9x^2-2x^3+9x^2-12\)
=-12
Bài 1:
a: Ta có: \(x\left(x^2+2\right)+2x\left(1-\dfrac{1}{2}x^2\right)=4\)
\(\Leftrightarrow x^3+2x+2x-x^3=4\)
hay x=1
b: Ta có: \(4x^2\left(x-1\right)+x\left(x^2+4x\right)=40\)
\(\Leftrightarrow4x^3-4x^2+x^3+4x^2=40\)
\(\Leftrightarrow5x^3=40\)
hay x=2
c: Ta có: \(3x\left(x-2\right)-3\left(x^2-3\right)=8\)
\(\Leftrightarrow3x^2-6x-3x^2+9=8\)
\(\Leftrightarrow-6x=-1\)
hay \(x=\dfrac{1}{6}\)
Bài 1: thực hiện phép tính
a, 2xy(x^2 + xy - 3y^2)
b, (x+2)(3x^2 - 4x)
c, (x^3 + 3x^2 - 8x - 20) : (x + 2)
d, (4x^2 - 4x - 4) : (x+4)
e, (2x^3 - 3x^2 + x - 2) : (x + 5)
f, (x+y)^2 + (x-y)^2 - 2(x+y)(x-y)
g, (a+b)^3 - (a-b)^3 - 2b^3
h, (x - y)(x + y)(x^2 + y^2)(x^4 + y^4)
i, 2x^2(x - 2) + 3x(x^2 - x - 2) - 5(3 - x^2)
k, (x - 1)(x - 3) - (4 - x)(2x + 1) - 3x^2 + 2x - 5
l, (x^4 - x^3 - 3x^2 + x + 2) : (x^2 - 1)
Bài 1: Nhân
a) 4x(3x-1)-2(3x+1)-(x+3)
b) (-2x^2-1xy+2y^2)(-1x^2y)
c) 4x(3x^2-x) -(2x+3)^2(6x^2-3x+1)
d) (x-2)(x+2)(x+4)
Bài 2: Tìm x
a) 4x(x-1)-3(x^2-5)-x^2=(x-3)(x+4)
b) 2(3x-1)(2x+5-6)(2x-1)(x+2)=6
c) 3(2x-1)(3x-1)-(2x-3)(9x-1)-3=-3
Bài 1:
a) \(4x\left(3x-1\right)-2\left(3x+1\right)-\left(x+3\right)\)
\(=12x^2-4x-6x-2-x-3\)
\(=12x^2-11x-5\)
b) \(=\left(-2x^2-1xy+2y^2\right)\left(-1x^2y\right)\)
\(=\left[\left(-1x^2y\right)\left(-2x^2\right)\right]-\left[\left(-1x^2y\right).1xy\right]+\left[\left(-1x^2y\right).2y^2\right]\)
\(=\left(2x^4y\right)-\left(-1x^3y^2\right)+\left(-2x^2y^3\right)\)
\(=2x^4y+1x^3y^2-2x^2y^3\)
c) \(4x\left(3x^2-x\right)-\left(2x+3\right)^2\left(6x^2-3x+1\right)\)
\(=\left(4x.3x^2\right)-\left(4x.x\right)-\left[\left(2x\right)^2+2.2x.3+3^2\right]\left(6x^2-3x+1\right)\)
\(=12x^3-4x^2-\left(4x^2+12x+9\right)\left(6x^2-3x+1\right)\)
\(=12x^3-4x^2-\left[4x^2\left(6x^2-3x+1\right)+12x\left(6x^2-3x+1\right)+9\left(6x^2-3x+1\right)\right]\)
\(=12x^3-4x^2-\left[\left(24x^4-12x^3+4x^2\right)+\left(72x^3-36x^2+12x\right)+\left(36x^2-27x+9\right)\right]\)
\(=12x^3-4x^2-24x^4+12x^3-4x^2-72x^3+36x^2-12x-36x^2+27x-9\)
\(=-48x^3-8x^2-24x^4+15x-9\)
Bài 1:
a) \(12x^2-11x-5\)
b,c,d tương tự.
a, 3x(4x-3)-(2x-1)(6x+5) b, 3x(x-1)²-2x(x+3)(x-3)+4x(x-4)
c, (x-1)³-(x-2)(x²-2x+4)+3(x+4)(x-4)
a: \(=12x^2-9x-\left(12x^2+10x-6x-5\right)\)
\(=12x^2-9x-12x^2-4x+5\)
=-13x+5
b: \(=3x\left(x^2-2x+1\right)-2x\left(x^2-9\right)+4x\left(x-4\right)\)
\(=3x^3-6x^2+3x-2x^3+18x+4x^2-16x\)
\(=x^3-2x^2+5x\)
c: \(=x^3-3x^2+3x-1-\left(x^3-8\right)+3\left(x^2-16\right)\)
\(=x^3-3x^2+3x-1-x^3+8+3x^2-48\)
\(=3x-41\)
Bài 1: Làm tính nhân
a) -3x^2 . ( 2x^3 - 2x + 1/3 )
b) ( x^4 + 2x^3 - 2/3 ) . ( -3x^4 )
c) ( x + 3 ) . ( x - 4 )
d) ( x - 4 ) . ( x^2 + 4x + 16 )
e) 4. ( x - 1/2 ) . ( x + 1/2 ) . ( 4x^2 + 1 )
Bài 2: Tìm x, biết
a) ( 2 - x ) . (x^2 + 2x + 4 ) + x . ( x - 3 ) . ( x + 4 ) - x^2 + 24 = 0
b) (x/2 + 3 ) . ( 5 - 6x ) + ( 12x - 2 ) . ( x/4 + 3 ) = 0
Bài 1: Làm tính nhân
a) -3x^2 . ( 2x^3 - 2x + 1/3 )
b) ( x^4 + 2x^3 - 2/3 ) . ( -3x^4 )
c) ( x + 3 ) . ( x - 4 )
d) ( x - 4 ) . ( x^2 + 4x + 16 )
e) 4. ( x - 1/2 ) . ( x + 1/2 ) . ( 4x^2 + 1 )
Bài 2: Tìm x, biết
a) ( 2 - x ) . (x^2 + 2x + 4 ) + x . ( x - 3 ) . ( x + 4 ) - x^2 + 24 = 0
b) (x/2 + 3 ) . ( 5 - 6x ) + ( 12x - 2 ) . ( x/4 + 3 ) = 0
1a) -3x2(2x3 - 2x + 1/3) = -6x5 + 6x3 - x2
b) (x4 + 2x3 - 2/3).(-3x4) = -3x8 - 6x7 + 2x4
c) (x + 3)(x - 4) = x2 - 4x + 3x - 12 = x2 - x - 12
d)(x - 4)(x2 + 4x + 16) = (x - 4)(x2 + 4x + 42) = x3 - 64
e) 4(x - 1/2)(x + 1/2)(4x2 + 1) =4(x2 - 1/4)(4x2 + 1) = 4(4x4 + x2 - x2 - 1/4) = 4(4x4 - 1/4) = 16x4 - 1
B2. a) (2 - x)(x2 + 2x + 4) + x(x - 3)(x + 4) - x2 + 24 = 0
=> 8 - x3 + x(x2 + 4x - 3x - 12) - x2 + 24 = 0
=> 8 - x3 + x3 + x2 - 12x - x2 + 24 = 0
=> -12x + 32 = 0
=> -12x = -32
=> x = -32 : (-12) = 8/3
b) (x/2 + 3)(5 - 6x) + (12x - 2)(x/4 + 3) = 0
=> 5x/2 - 3x2 + 15 - 18x + 3x2 + 36x - x/2 - 6 = 0
=> 20x + 9 = 0
=> 20x = -9
=> x = -9/20