![](https://rs.olm.vn/images/avt/0.png?1311)
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(A=3x^2-5xy+2y^2-2y+2012\)
\(=3x^2-3xy-2xy+2y^2-2y+2012\)
\(=\left(x-y\right)\left(3x-2y\right)-2y+2012\)
\(=6x-4y-2y+2012\)
\(=6\left(x-y\right)+2012\)
=12+2012=2024
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
P(x)+Q(x)
=3x^2y-2x+5xy^2-7y^2+3xy^2-7y^2-9x^2y-x-5
=8xy^2-14y^2-6x^2y-3x-5
=>Chọn A
![](https://rs.olm.vn/images/avt/0.png?1311)
\(P=\dfrac{1}{3}x^2y+xy^2-xy+\dfrac{1}{2}xy^2-5xy-\dfrac{1}{3}x^2y=\dfrac{3}{2}xy^2-6xy\)
Thay x = 2 ; y = 1 ta được
\(\dfrac{3}{2}.2.1-6.2.1=3-12=-9\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Mình viết lại cho dễ đọc.
a) A+ x2+4xy + x2- y2 = 2y +3xy- 5x2y +5x2y + 2x2y2
b) A- ( -2 x3) -y2+ 32x2- 4xy - y = 10z2 + y2z2
c) A= -2x + 5xy - 3x2y + 2x2y2 - 2 y2x
B= xy- 3x2y+ 2x2y + 2x2y2 - 2- y2x
![](https://rs.olm.vn/images/avt/0.png?1311)
2: Thay \(x=\dfrac{1}{2}\) và y=2 vào M, ta được:
\(M=\dfrac{2\cdot\left(\dfrac{1}{2}\right)^2\cdot2-1.2\cdot\left(3\cdot\dfrac{1}{2}-2\cdot2\right)}{\dfrac{1}{2}\cdot2}\)
\(=4\cdot\dfrac{1}{4}-1.2\left(\dfrac{3}{2}-4\right)\)
\(=1-1.8+4.8\)
\(=4\)
1: Ta có: \(\left(-\dfrac{2}{3}x^3y^2\right)z\cdot5xy^2z^2\)
\(=\left(-\dfrac{2}{3}\cdot5\right)\cdot\left(x^3\cdot x\right)\cdot\left(y^2\cdot y^2\right)\cdot\left(z\cdot z^2\right)\)
\(=\dfrac{-10}{3}x^4y^4z^3\)
![](https://rs.olm.vn/images/avt/0.png?1311)
a: M=3/4xy^2-2x^2y+2y^3-1/3x^2+1/2x^2y-5xy^2+x^3-y^3
=y^3-1/3x^2+x^3-17/4xy^2-3/2x^2y