bài 1 : thực hiện phép tính
a) (4x - 1)(2 - x)-(2x-1)^2
b) (15x^4y^5-30x^3y^4+35x^3y^4): (5x^3y^3)
Bài 3:
3: \(6x\left(x-y\right)-9y^2+9xy\)
\(=6x\left(x-y\right)+9xy-9y^2\)
\(=6x\left(x-y\right)+9y\left(x-y\right)\)
\(=\left(x-y\right)\left(6x+9y\right)\)
\(=3\left(2x+3y\right)\left(x-y\right)\)
Bài 4:
thực hiện các phép tính sau:
a,3x^2.(2x^3-x+5)=6x^5-3x^3+15x^2
b,(4xy+3y-5x)x^2y=4x^3y^2+3x^2y^2-5x^3y
Answer:
\(3x^2.\left(2x^3-x+5\right)\)
\(=3x^2.2x^3+3x^2.(-x)+3x^2.5\)
\(=6x^5-3x^3+15x^2\)
\((4xy+3y-5x).x^2y\)
\(=4xy.x^2y+3y.x^2y-5x.x^2y\)
\(=4x^3+3x^2y^2-5x^3y\)
Thực hiện phép tính:
a) x.(x+2); b) (3xy-8).(5xy+5); c) (1+x).(x-1); d) (2x-1).(x^2+5-4); e) (6x^5y^2 - 9x^4y^3 + 15x^3y^4): 3x^3y^2 f) (2x3 - 21x2 + 67x - 60) : (x - 5)
f: \(=\dfrac{2x^3-10x^2-11x^2+55x+12x-60}{x-5}=2x^2-11x+12\)
Bài 1: (4 điểm) Thực hiện phép tính:
a/ \(\dfrac{1-x}{x^2-2x+1}+\dfrac{x+1}{x-1}\) b/ \(\dfrac{2x}{3y^4z}.\left(-\dfrac{4y^2z}{5x}\right).\left(-\dfrac{15y^3}{8xz}\right)\)
a) Ta có: \(\dfrac{1-x}{x^2-2x+1}+\dfrac{x+1}{x-1}\)
\(=\dfrac{1-x}{\left(x-1\right)^2}-\dfrac{x+1}{1-x}\)
\(=\dfrac{1-x}{\left(1-x\right)^2}-\dfrac{x+1}{1-x}\)
\(=\dfrac{1-x-1}{1-x}=\dfrac{-x}{1-x}=\dfrac{x}{x-1}\)
b) Ta có: \(\dfrac{2x}{3y^4z}\cdot\left(-\dfrac{4y^2z}{5x}\right)\cdot\left(-\dfrac{15y^3}{8xz}\right)\)
\(=\dfrac{2x\cdot4y^2z\cdot15y^3}{3y^4z\cdot5x\cdot8xz}\)
\(=\dfrac{120xy^5z}{120x^2y^4z^2}=\dfrac{y}{xz}\)
thực hiện phép tính
a) (x+3y)(2x^2y -6xy^2)
b) (6x^5y^2 -9x^4y^3 +15x^3y^4) : 3x^3y^2
c) (2x+3)^2 + (2x+5)^2 -2(2x+3)(2x+5)
d) (y+3)^3 -(3-y)^2 -54y
a) (x + 3y) (2x2y - 6xy2)
= (x + 3y) + 2xy (x - 3y)
= 2xy [(x + 3y) (x - 3y)]
= 2xy (x2 - 3y2)
b) (6x5y2 - 9x4y3 + 15x3y4) : 3x3y2
= (6x5y2 : 3x3y2) + (-9x4y3 : 3x3y2) + (15x3y4 : 3x3y2)
= [(6 : 3) (x5 : x3) (y2 : y2)] + [(-9 : 3) (x4 : x3) (y3 : y2)] + [(15 : 3) (x3 : x3) (y4 : y2)]
= 2x2 + (-3xy) + 5y2
= 2x2 - 3xy + 5y2
#Học tốt!!!
Thực hiện các phép tính sau a) 3y/28^2 . 2x/7y^4.49x^4y^3 b) (-20x/3y^2) : (-4x^3/5y) c) 4x+12/(x+4)^2 : 3(x+3)/x+4
Thực hiện phép tính :
a/ (x - 1)^2 - (4x + 3) (2 - x)
b/ (15x^3y^2 - 6x^2y^3) : 3x^2y^2 = (15x^3y^2 : 3x^2y^2) - (6x^2y^3 : 3x^2y^2) = 5x - 2y
c/\(\dfrac{x+7}{x-7}\) - \(\dfrac{x-7}{x+7}\) +\(\dfrac{4x^2}{x^2-49}\)
a/ (x-1)2-(4x+3)(2-x)=x2-2x+1-(8x-4x2+6-3x)
=x2-2x+1-8x+4x2-6+3x=5x2-7x-6
b/ (15x3y2 - 6x2y3) : 3x2y2 = 5x - 2y
c/ \(\dfrac{x+7}{x-7}-\dfrac{x-7}{x+7}+\dfrac{4x^2}{x^2-49}\)=\(\dfrac{\left(x+7\right)^2-\left(x-7\right)^2+4x^2}{\left(x-7\right)\left(x+7\right)}\)=\(\dfrac{x^2+14x+49-\left(x^2-14x+49\right)+4x^2}{\left(x-7\right)\left(x+7\right)}\)=\(\dfrac{28x+4x^2}{\left(x-7\right)\left(x+7\right)}\)=\(\dfrac{4x\left(x+7\right)}{\left(x-7\right)\left(x+7\right)}\)=\(\dfrac{4x}{x-7}\)
Bài 1: Thực hiện phép tính
a) (2x+3)2
b) (x-2/5)3
c) (4x2+1)3
d)(-1/3x-y)3
e) (x+4)3
f) (2x-3y)3
Bài 1: Thực hiện các phép tính sau:
a)-2xy^2(x^3y-2x^2y^2+5xy^3)
b)(-2x)(x^3-3x^2-x+1)
c)(-10x^3+2/5y-1/3z)(-1/2zy)
d)3x^2(2x^3-x+5)
e)(4xy+3y-5x)x^2y
f)(3x^2y-6xy+9x)(-4/3xy)
\(a,-2xy^2\left(x^3y-2x^2y^2+5xy^3\right)\\ =-2x^4y^3+4x^3y^4-10x^2y^5\\ b,\left(-2x\right)\left(x^3-3x^2-x+1\right)\\ =-2x^4+6x^3+2x^2-2x\\ c,\left(-10x^3+\dfrac{2}{5}y-\dfrac{1}{3}z\right)\left(-\dfrac{1}{2}zy\right)\\ =5x^3yz-\dfrac{1}{5}y^2z+\dfrac{1}{6}yz^2\\ d,3x^2\left(2x^3-x+5\right)=6x^5-3x^3+15x^2\\ e,\left(4xy+3y-5x\right)x^2y=4x^3y^2+3x^2y^2-5x^3y\\ f,\left(3x^2y-6xy+9x\right)\left(-\dfrac{4}{3}xy\right)\\ =-4x^3y^2+8x^2y^2-12x^2y\)