3xy+2y+y=1
4xy-3y-5y=1
5x2+3y2=45
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dài quá mình làm 3 câu đầu thôi nhé!
a)7x^2-14xy
=7x(x-2y)
b) 3x^2-6xy+3y^2
=3(x^2-2xy+y^2)
c) x^2-4z^2-2xy+y^2
=(x^2-2xy+y^2)-4z^2
=(x-y-2z)(x-y+2z)
=3(x-y)^2
c)
\(a,\Leftrightarrow\left\{{}\begin{matrix}5x+15y=-10\\5x-4y=11\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}19y=-21\\5x-4y=11\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}y=-\dfrac{21}{19}\\5x-4\left(-\dfrac{21}{19}\right)=11\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{25}{19}\\y=-\dfrac{21}{19}\end{matrix}\right.\)
\(c,\Leftrightarrow\left\{{}\begin{matrix}3x+5y=1\\10x-5y=-40\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}3x+5y=1\\13x=-39\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-3\\y=2\end{matrix}\right.\\ d,\Leftrightarrow\left\{{}\begin{matrix}5x-10y=-30\\5x-3y=5\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}5x-3y=5\\-7y=-35\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=4\\y=5\end{matrix}\right.\\ e,\Leftrightarrow\left\{{}\begin{matrix}2\left(x+y\right)+3\left(x-y\right)=4\\2\left(x+y\right)+4\left(x-y\right)=10\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x-y=6\\2\left(x+y\right)+3\cdot6=4\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}x-y=6\\x+y=-7\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=-\dfrac{1}{2}\\y=-\dfrac{13}{2}\end{matrix}\right.\)
a) \(P=3\left(x^2+2xy+y^2\right)-2\left(x+y\right)-100\)
\(P=3\left(x+y\right)^2-2.5-100\)
\(P=3.5^2-110\)
\(P=-35\)
b) \(Q=\left[x^3+y^3+3xy\left(x+y\right)\right]-2\left(x^2+2xy+y^2\right)+3.5+10\)
\(Q=\left(x+y\right)^3-2\left(x+y\right)^2+25\)
\(Q=5^3-2.5^2+25\)
\(Q=100\)
a) 10x(x-y) - 6y(y-x)
= 10x(x-y) +6y ( x-y)
=(10x+6y) (x-y)
b) 3x2 + 5y - 3xy -5x
= 3x(x-y) + 5(y-x)
= 3x(x-y) -5(x-y)
= (3x-5) ( x-y)
c) 3y2 - 3z2 +3x2 + 6xy
=3(y2 - z2 + x2 + 2xy)
=3[(x2 +2xy+y2)-z2 ]
=3[(x+y)2 - z2 ]
=3(x+y-z) (x+y+z)
d) 16x3 + 54y3
=2(8x3 + 27y3 )
=2[(2x)3 + (3y)3 ]
=2(2x+3y) (4x2 - 6xy + 9y2 )
e) x2 - 25 -2xy+y2
=(x2-2xy+y2)-25
=(x-y)2 -52
=(x-y-5) (x-y+5)
f) (mình chưa làm ra )
{mong m.n bổ sung thêm..}
mấy câu trên bạn kia đã trả lời rồi nên mk k làm lại nx
f, x5 - 3x4 + 3x3 - x2
= x2 (x3 - 3x2 + 3x -1)
= x2 (x - 1)3
Chúc bạn học tốt!
\(a,=\dfrac{2y^4}{3x\left(2x-3y\right)}\\ b,=-\dfrac{2y\left(3x-1\right)^2}{3x^2}\\ c,=\dfrac{5\left(4x^2-9\right)}{\left(2x+3\right)^2}=\dfrac{5\left(2x-3\right)\left(2x+3\right)}{\left(2x+3\right)^2}=\dfrac{5\left(2x-3\right)}{2x+3}\\ d,=\dfrac{5x\left(x-2y\right)}{-2\left(x-2y\right)^3}=-\dfrac{5x}{2\left(x-2y\right)^2}\)