tick mik nha

\(x^2+y^2=\left(x+y\right)^2-2xy=m^2-2n\\ x^3+y^3=\left(x+y\right)^3-3xy\left(x+y\right)=m^3-3mn\\ \Rightarrow x^5+y^5=\left(x^3+y^3\right)\left(x^2+y^2\right)-x^2y^2\left(x+y\right)=\left(m^3-3mn\right)\left(m^2-2n\right)-n^2m\\ \Rightarrow x^7+y^7=\left(x^2+y^2\right)\left(x^5+y^5\right)-x^2y^2\left(x^3+y^3\right)=.....\)

hi

1h ô tô đi dc 1/4 quãng đường

nên ô tô đi 2/3 quãng đường hết

2/3  :  1/4=8/3 giờ

2^x+3+2^x=72

2^x.2³+2^x=72

2^x.(2³+1)=72

<=>2^x.9=72

<=>2^x=8

<=>x=3

a,x(2x-1)-(x-1)^2-x^2=0

<=>x(2x-1-x)-(x-1)^2=0

<=>x(x-1)-(x-1)^2=0

<=>(x-x+1)(x-1)=0

<=>x-1=0

<=>x=1

b,(x+2)^3-x^3-6x^2=4

<=>x^3+6x^2+12x+8-x^3-6x^2=4

<=>12x+8=4

<=>x=-1/3

tick mik nha

a,(x-1/4)^2=0

<=>x-1/4=0

<=>x=1/4

b,\(\left(x+\dfrac{1}{3}\right)^2=4\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{3}=2\\x+\dfrac{1}{3}=-2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{3}\\x=-\dfrac{7}{3}\end{matrix}\right.\)

tick mik nha

d,-3x^2+2x-5=-3(x^2-2/3x)-5=-3(x^2-2x.1/3)-5=-3(x^2-2x.1/3+1/9)-5+1/3

                    =-3(x-1/3)^2-14/3\(\le\)-14/3

dấu = xảy ra khi x=1/3

tick mik 4 cái nha bạn

-x^2+10x-5=-(x^2-10x+25)+20\(\le\)20

dấu = xảy ra khi x=5