![](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)
Ta có: P = x2y + x3 – xy2 + 3 và Q = x3 + xy2 - xy - 6
nên P + Q = (x2y + x3 – xy2 + 3) + (x3 + xy2 - xy - 6)
= x2y + x3 – xy2 + 3 + x3 + xy2 - xy - 6
= (x3 + x3) + x2y + (xy2 - xy2) - xy + (3 - 6)
= 2x3 + x2y - xy -3.
Ta có: P = x2y + x3 – xy2 + 3 và Q = x3 + xy2 - xy - 6
nên P + Q = (x2y + x3 – xy2 + 3) + (x3 + xy2 - xy - 6)
= x2y + x3 – xy2 + 3 + x3 + xy2 - xy - 6
= (x3 + x3) + x2y + (xy2 - xy2) - xy + (3 - 6)
= 2x3 + x2y - xy -3.
![](https://rs.olm.vn/images/avt/0.png?1311)
a: A+B=x+2y+x-2y=2x
A-B=x+2y-x+2y=4y
b: A+B
=2x^2y-x^3-xy^2+1+x^3+xy^2-2
=2x^2y-1
A-B
=2x^2y-x^3-xy^2+1-x^3-xy^2+2
=-2x^3+2x^2y-2xy^2+3
c: A+B
=x^2-2yz+z^2+3yz+5x^2-z^2
=6x^2+yz
A-B
=x^2-2yz+z^2-3yz-5x^2+z^2
=-4x^2+2z^2-5yz
![](https://rs.olm.vn/images/avt/0.png?1311)
Ta có: P = x2y + x3 – xy2 + 3 và Q = x3 + xy2 - xy - 6
nên P + Q = (x2y + x3 – xy2 + 3) + (x3 + xy2 - xy - 6)
= x2y + x3 – xy2 + 3 + x3 + xy2 - xy - 6
= (x3 + x3) + x2y + (xy2 - xy2) - xy + (3 - 6)
= 2x3 + x2y - xy -3.
P+Q=(x2y+x3-xy2+3)+(x3+ xy2-xy-6 )
=x2y+x3-xy2+3+x3+ xy2-xy-6
=x2y+(x3+x3)+(-xy2+xy2)+(3-6)+(-xy)
=x2y + 2x3 - 3 - xy
![](https://rs.olm.vn/images/avt/0.png?1311)
a)\(P+Q=\left(x^2y+xy^2-5x^2y^2+x^3\right)+\left(3xy^2-x^2y+x^2y^2\right)\)
=\(x^2y+xy^2-5x^2y^2+x^3+3xy^2-x^2y+x^2y^2\)
=\(x^2y-x^2y+xy^2+3xy^2-5x^2y^2+x^2y^2+x^3\)
=\(4xy^2-4x^2y^2+x^3\)
b)\(M+N=\left(x^3+xy+y^2-x^2y^2-2\right)+\left(x^2y^2+5-y^2\right)\)
=\(x^3+xy+y^2-x^2y^2-2+x^2y^2+5-y^2\)
=\(x^3+xy+y^2-y^2-x^2y^2+x^2y^2-2+5\)
=\(x^3+xy+3\)
Bài dài nên chắc sẽ có sai sót, nếu đúng bạn nha
![](https://rs.olm.vn/images/avt/0.png?1311)
a) Ta có: P = x2y + xy2 – 5x2y2 + x3 và Q = 3xy2 – x2y + x2y2
=> P + Q = x2y + xy2 – 5x2y2 + x3 + 3xy2 – x2y + x2y2
= x3 – 5x2y2 + x2y2 + x2y – x2y + xy2 + 3xy2
= x3 – 4x2y2 + 4xy2
b) Ta có: M = x3 + xy + y2 – x2y2 – 2 và N = x2y2 + 5 – y2.
=> M + N = x3 + xy + y2 – x2y2 – 2 + x2y2 + 5 – y2
= x3 – x2y2 + x2y2 + y2 – y2 + xy - 2 + 5
= x3 + xy + 3.
a)
P + Q = x2y + xy2 – 5x2y2 + x3 + 3xy2 – x2y + x2y2
= x3 – 5x2y2 + x2y2 + x2y – x2y + xy2 + 3xy2
= x3 – 4x2y2 + 4xy2
b)
M + N = x3 + xy + y2 – x2y2 – 2 + x2y2 + 5 – y2
= x3 – x2y2 + x2y2 + y2 – y2 + xy - 2 + 5
= x3 + xy + 3.
![](https://rs.olm.vn/images/avt/0.png?1311)
\(B=\dfrac{3}{4}xy^2-\dfrac{1}{3}x^2y-\dfrac{5}{6}xy^2+2x^2y=-\dfrac{1}{12}xy^2+\dfrac{5}{3}x^2y\)
Bậc:3
Thay x=-1, y=1 vào B ta có:
\(B=-\dfrac{1}{12}xy^2+\dfrac{5}{3}x^2y=-\dfrac{1}{12}.\left(-1\right).1^2+\dfrac{5}{3}.\left(-1\right)^2.1=\dfrac{1}{12}+\dfrac{5}{3}=\dfrac{7}{4}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
a) Ta có M = x2y + 0,5xy3 – 7,5x3y2 + x3 và N = 3xy3 – x2y + 5,5x3y2.
=> M + N = x2y + 0,5xy3 – 7,5x3y2 + x3 + 3xy3 – x2y + 5,5x3y2
= – 7,5x3y2 + 5,5x3y2 + x2y – x2y + 0,5xy3 + 3xy3 + x3
= -2x3y2 + 3,5xy3 + x3
b) P = x5 + xy + 0,3y2 – x2y3 – 2 và Q = x2y3 + 5 – 1,3y2.
=> P + q = (x5 + xy + 0,3y2 – x2y3 – 2) + (x2y3 + 5 – 1,3y2)
= x5 + xy + 0,3y2 – x2y3 – 2 + x2y3 + 5 – 1,3y2
= x5 – x2y3 + x2y3 + 0,3y2 – 1,3y2 + xy - 2 + 5
= x5 - y2 + xy + 3.
P+Q=x2y+x3-xy2+3+x3+xy2-xy-6
=-xy2+xy2+x3+x3+3-6+x2y
=2x3-3+x2y
vậy P+Q=2x3-3+x2y