Tính:
a) 2xzy2 . 3x2yzb)x4y5 . 8xy2
c) -3x2y4 . ½ xy5 d) x4y2z . xy2z3
e )x3- 7x3 + (- 2x3) f) xy - 7xy+xy
g) xy2 - xy2 + xy2 h) xyz2 - 2xyz2 - 3xyz2
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\(a,=3x^3y^3-3x^2y^3+3x^2y^4+3xy^5\\ b,=\left(2x^3-6x^2+10x-3x^2+9x-15\right):\left(x^2-3x+5\right)\\ =\left[2x\left(x^2-3x+5\right)-3\left(x^2-3x+5\right)\right]:\left(x^2-3x+5\right)\\ =2x-3\\ c,=\left[x^2\left(x-3\right)+\left(x-3\right)\right]:\left(x-3\right)=x^2+1\)
a) \(3x\left(5x^2-2x-1\right)\)
\(=3x.5x^2-3x.2x+3x.\left(-1\right)\)
\(=15x^3-6x^2-3x\)
b) \(\left(x^3-2xy+3\right)\left(-xy\right)\)
\(=\left(-xy\right).\left(x^2+2xy-3\right)\)
\(=\left(-xy\right).x^2+\left(-xy\right).2xy+\left(-xy\right).\left(-3\right)\)
\(=x^3y-2x^2y^2+3xy\)
mấy câu sau vt lại đè
c)x2y(2x3 - xy2 - 1);
d)x(1,4x - 3,5y);
e)xy(x2 - xy + y2);
f)(1 + 2x - x2)5x;
g) (x2y - xy + xy2 + y3). 3xy2;
h) x2y(15x - 0,9y + 6);
Đây ạ giúp mik vs bt tết đs mng :<
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
Vậy P + Q = 2x3 + x2y – xy – 3.
Ta có:
• P + Q = (x2y + x3 – xy2 + 3) + (x3 + xy2 – xy – 6)
= x2y + x3 – xy2 + 3 + x3 + xy2 – xy – 6
= x2y + (x3 + x3) + (xy2 – xy2) – xy + (3 – 6)
= x2y + 2x3 – 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) + xy + (6 + 3)
= x2y – 2xy2 + xy + 9.
Vậy P + Q = x2y + 2x3 – xy – 3; P – Q = x2y – 2xy2 + xy + 9.
\(\text{ P + Q = (x^2y + x^3 – xy^2 + 3) + (x^3 + xy^2 – xy – 6)}\)
\(\text{= x^2y + x^3 – xy^2 + 3 + x^3 + xy^2 – xy – 6}\)
\(\text{= x^2y + (x^3 + x^3) + (xy^2 – xy^2) – xy + (3 – 6)}\)
\(\text{= x^2y + 2x^3 – xy – 3}\)
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\(\text{P – Q = (x^2y + x^3 – xy^2 + 3) – (x^3 + xy^2 – xy – 6)}\)
\(\text{= x^2y + x^3 – xy^2 + 3 – x^3 – xy^2 + xy + 6}\)
\(\text{= x^2y + (x^3 – x^3) – (xy^2 + xy^2) + xy + (6 + 3)}\)
\(\text{= x^2y – 2xy^2 + xy + 9}\)
1: \(A=2x^3y^4-5x\cdot x^2y^4+xy^2\cdot x^2y^2=-2x^3y^4=-2\cdot\left(-1\right)^3\cdot\dfrac{1}{16}=\dfrac{1}{8}\)
2: \(B=9x^4y^6\cdot\left(-4xy\right)+19x^3y^5\cdot\left(-2\right)x^2y^2\)
\(=-36x^5y^7-38x^5y^7\)
\(=-74x^5y^7=-74\cdot\left(-1\right)^5\cdot2^7=9472\)
3: \(f\left(-1\right)=3\cdot\left(-1\right)^4+7\cdot\left(-1\right)^3+4\cdot\left(-1\right)^2-2\cdot\left(-1\right)-2=0\)
\(f\left(1\right)=3+7+4-2-2=10\)
\(A=5x^2y-xy^2+4xy+6\) bậc : 3
a)\(B=-5x^2y+xy^2-4xy-6\)
b)\(=>C=-2xy+1-5x^2y+xy^2-4xy-6\)
\(C=-5x^2y+xy^2-6xy-5\)
a/ \(P+Q=\left(x^2y+x^3-xy^2+3\right)+\left(x^3+xy^2-xy-6\right)\)
\(=x^2y+x^3-xy^2+3+x^3+xy^2-xy-6\)
\(=\left(x^3+x^3\right)+\left(xy^2-xy^2\right)+\left(3-6\right)+x^2y-xy\)
\(=2x^3+x^2y-xy-3\)
b/ \(M+N=\left(x^2y+0,5xy^3-7,5x^3y^2+x^3\right)+\)
\(\left(3xy^3-x^2y+5,5x^3y^2\right)\)
\(=x^2y+0,5xy^3-7,5x^3y^2+x^3+3xy^3-x^2y+5,5x^3y^2\)
\(=\left(x^2y-x^2y\right)+\left(0,5xy^3+3xy^3\right)+\left(5,5x^3y^2-7,5x^3y^2\right)+x^3\)
\(=3,5xy^3-2x^3y^2+x^3\)