3.
\(a.M=y^2-2y+\dfrac{1}{2}y^2+5y-y^2\)
\(M=\left(y^2+\dfrac{1}{2}y^2-y^2\right)+\left(-2y+5y\right)\)
\(M=\dfrac{1}{2}y^2+3y\)
4.
\(a.A=2x^2+x-\dfrac{1}{2}x^2+5x\)
\(A=\left(2x^2-\dfrac{1}{2}x^2\right)+\left(x+5x\right)\)
\(A=\left(2-\dfrac{1}{2}\right)x^2+\left(1+5\right)x\)
\(A=\dfrac{3}{2}x^2+6x\)
\(b.B=5xy+\dfrac{1}{2}x^2y+2x^2y\)
\(B=\left(5+\dfrac{1}{2}+2\right)x^2y\)
\(B=\dfrac{7}{2}x^2y\)
\(c.C=2x^3-2xy+x^2+xy-x^2-\dfrac{1}{2}x^3\)
\(C=\left(2x^3-\dfrac{1}{2}x^3\right)+\left(-2xy+xy\right)+\left(x^2-x^2\right)\)
\(C=\left(2-\dfrac{1}{2}\right)x^3+\left(-2+1\right)xy\)
\(C=\dfrac{3}{2}x^3-xy\)
Bài 3:
a, \(M=y^2-2y+\dfrac{1}{2}y^2+5y-y^2-=\dfrac{1}{2}y^2+3y\)
b, \(P=\dfrac{1}{3}x^2+xy^2-xy+\dfrac{1}{2}xy^2-5xy-\dfrac{1}{3}x^2y=\dfrac{1}{3}x^2+\dfrac{3}{2}xy^2-6xy-\dfrac{1}{3}x^2y\)
3:
a: M=y^2-2y+1/2y^2+5y-y^2
=y^2-y^2+1/2y^2-2y+5y
=1/2y^2+3y
b: \(P=\dfrac{1}{3}x^2+xy^2+\dfrac{1}{2}xy^2-xy-5xy-\dfrac{1}{3}x^2y\)
=1/3x^2+3/2xy^2-6xy-1/3x^2y
4:
a: M=2x^2-1/2x^2+5x+x=3/2x^2+6x
b: B=5xy+x^2y(1/2+2)
=5/2x^2y+5xy
c: =2x^3-1/2x^3+x^2-x^2-2xy+5xy
=3xy+3/2x^3
Bài 4
a, \(A=2x^2+x-\dfrac{1}{2}x^2+5x=\dfrac{3}{2}x^2+6x\)
b, \(B=5xy+\dfrac{1}{2}x^2y+2x^2y=5xy+\dfrac{5}{2}x^2y\)
c, \(C=2x^3-2xy+x^2+5xy-x^2-\dfrac{1}{2}x^3=\dfrac{3}{2}x^3+3xy\)
