nhanh nhanh đươch không ạ

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\(3^{m-1}.5^{n+1}=45^{m+n}\)

\(\Leftrightarrow3^{m-1}.5^{n+1}=\left(3^2.5\right)^{m+n}\)

\(\Leftrightarrow3^{m-1}.5^{n+1}=3^{2.\left(m+n\right)}.5^{m+n}\)

Khi đó ta có: \(\left\{{}\begin{matrix}m-1=2\left(m+n\right)\\n+1=m+n\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}m-1=2m+2n\\n+1=m+n\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}m=-1-n\\m=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}m=1\\n=-2\end{matrix}\right.\)

Vậy \(m=1;n=-2\)

2)

a)Ta có: 2m+5=n.(m-1)

=> 2m+5=nm-n

=>2m+5-nm+n=0

=>(2-n).m+5+n=0

=>(2-n).m-(2-n)+5+2=0

=>(2-n).(m-1)+7=0

=>(2-n).(m-1)=-7=-1.7=-7.1

Ta có bảng sau:

Vậy (n,m)=(1,-6),(9,2),(3,8),(-5,0)

a/Ta có: M(x)+N(x) = (2x⁵ - 4x³ + 2x² + 10x - 1) + (-2x⁵ + 2x⁴ + 4x³ + x² + x - 10)

                              = 2x⁵ - 2x⁵ - 4x³ + 4x³ + 2x⁴ + 2x² + x² + 10x + x -1 - 10

                              = 2x⁴ + 3x² + 11x - 11

b/ Ta có: A(x) = N(x)-M(x) = (-2x⁵ + 2x⁴ + 4x³ + x² + x - 10) - (2x⁵ - 4x³ + 2x² + 10x - 1)

                                         = -2x⁵ - 2x⁵ + 2x⁴ + 4x³ + 4x³ + x² - 2x² + x - 10x -10 + 1

                                         = -2x⁵ + 2x⁴ + 8x³ - x² - 9x -9