Làm tính nhân :
a) \(\left(2x^2-3x\right)\left(5x^2-2x+1\right)\)
b) \(\left(x-2y\right)\left(3xy+5y^2+x\right)\)
K
Khách
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Những câu hỏi liên quan
12 tháng 6 2022
a: \(=-3x^3y^3-3x^2y^2+2x^2y\)
b: \(=6x^2+12x-2x-4\)
\(=6x^2+10x-4\)
c: \(=6x^3y^3+10x^2y^2-2x^2y\)
d: \(=2x^2-3x-2x+3\)
\(=2x^2-5x+3\)
15 tháng 7 2020
a) Ta có: \(5x^2-3x\left(x+2\right)\)
\(=5x^2-3x^2-6x\)
\(=2x^2-6x\)
b) Ta có: \(3x\left(x-5\right)-5x\left(x+7\right)\)
\(=3x^2-15x-5x^2-35x\)
\(=-2x^2-50x\)
c) Ta có: \(3x^2y\left(2x^2-y\right)-2x^2\left(2x^2y-y^2\right)\)
\(=3x^2y\left(2x^2-y\right)-2x^2y\left(2x^2-y\right)\)
\(=x^2y\left(2x^2-y\right)=2x^4y-x^2y^2\)
d) Ta có: \(3x^2\left(2y-1\right)-\left[2x^2\cdot\left(5y-3\right)-2x\left(x-1\right)\right]\)
\(=6x^2y-3x^2-\left[10x^2y-6x^2-2x^2+2x\right]\)
\(=6x^2y-3x^2-10x^2y+6x^2+2x^2-2x\)
\(=-4x^2y+5x^2-2x\)
e) Ta có: \(4x\left(x^3-4x^2\right)+2x\left(2x^3-x^2+7x\right)\)
\(=4x^4-16x^3+4x^4-2x^3+14x^2\)
\(=8x^4-18x^3+14x^2\)
f) Ta có: \(25x-4\left(3x-1\right)+7x\left(5-2x^2\right)\)
\(=25x-12x+4+35x-14x^3\)
\(=-14x^3+48x+4\)
20 tháng 4 2017
Bài giải:
a) (-2x5 + 3x2 – 4x3) : 2x2 = (- )x5 – 2 + x2 – 2 + (-)x3 – 2 = - x3 + – 2x.
b) (x3 – 2x2y + 3xy2) : (- x) = (x3 : -x) + (-2x2y : -x) + (3xy2 : -x)
= -2x2 + 4xy – 6y2
c)(3x2y2 + 6x2y3 – 12xy) : 3xy = (3x2y2 : 3xy) + (6x2y2 : 3xy) + (-12xy : 3xy)
= xy + 2xy2 – 4.
20 tháng 4 2017
a) (-2x5+3x2-4x3) : 2x2
= (-2x5:2x2)-(4x3:2x2)+(3x2:2x2)
= -x3-2x+\(\dfrac{3}{2}\)
b) \(\left(x^3-2x^2y+3xy^2\right):\left(-\dfrac{1}{2}x\right)\)
= \(\left(x^3:\dfrac{-1}{2}x\right)+\left(-2x^2y:\dfrac{-1}{2}x\right)+\left(3xy^2:\dfrac{-1}{2}x\right)\)
= \(-2x^2+4xy-6y^2\)
c) \(\left(3x^2y^2+6x^2y^3-12xy\right):3xy\)
= \(\left(6x^2y^3:3xy\right)+\left(3x^2y^2:3xy\right)+\left(-12xy:3xy\right)\)
= \(xy^2+xy-4\)
20 tháng 3 2019
b)\(\sqrt{5x^2+2xy+2y^2}+\sqrt{2x^2+2xy+5y^2}=3\left(x+y\right)\)
\(\Rightarrow\left(\sqrt{5x^2+2xy+2y^2}+\sqrt{2x^2+2xy+5y^2}\right)^2=\left(3\left(x+y\right)\right)^2\)
\(\Leftrightarrow\sqrt{\left(5x^2+2xy+2y^2\right)\left(2x^2+2xy+5y^2\right)}=x^2+7xy+y^2\)
\(\Rightarrow\left(5x^2+2xy+2y^2\right)\left(2x^2+2xy+5y^2\right)=\left(x^2+7xy+y^2\right)^2\)
\(\Leftrightarrow9\left(x-y\right)^2\left(x+y\right)^2=0\)\(\Leftrightarrow\left[{}\begin{matrix}x=y\\x=-y\end{matrix}\right.\)
\(\rightarrow\left(x;y\right)\in\left\{\left(0;0\right),\left(1;1\right)\right\}\)
21 tháng 10 2020
cau a : (3x^2y-6xy+9x)(-4/3xy)
=-4/3xy.3x^2y+4/3xy.6xy-4/3xy.9x
=-4x+8-8y
cau b : (1/3x+2y)(1/9x^2-2/3xy+4y^2)
=(1/3)^3-2/9x^2y+8y^3+4/3xy^2+2/9x^2y-4/3xy^2+8y^3
=(1/3)^3 + (2y)^3x-2
cau c : (x-2)(x^2-5x+1)+x(x^2+11)
=x^3-5x^2+x-2x^2+10x-2+x^3+11x
=2x^3-7x^2+22x-2
cau d := x^3 + 6xy^2 -27y^3
cau e := x^3 + 3x^2 -5x - 3x^2y - 9xy = 15y
cau f := x^2-2x+2x -4-2x-1
= x(x-2)-5
14 tháng 8 2021
a: \(3x^2y\left(2x^2-xy+5y^2\right)=6x^4y-3x^3y^2+15x^2y^3\)
b: \(\left(x+2\right)\left(x^2+3x-4\right)\)
\(=x^3+3x^2-4x+2x^2+6x-8\)
\(=x^3+5x^2+2x-8\)
a) \((2x^2−3x)(5x^2−2x+1)\)
\(=2x^2.5x^2−2x^2.2x+2x^2−3x.5x^2+3x.2x−3x\)
\(=10x^4−4x^3+2x^2−15x^3+6x^2−3x\)
\(=10x^4−19x^3+8x^2−3x\)
b) \((x−2y)(3xy+5y^2+x)\)
\(=x.3xy+x.5y^2+x.x−2y.3xy−2y.5y^2−2y.x\)
\(=3x^2y+5xy^2+x^2−6xy^2−10y^3−2xy\)
\(=3x^2y−xy^2−2xy+x^2−10y^3\)