câu e mik viết sai đề,lm theo anh Thịnh,còn câu g thì theo mik :)

e)x³-4x+14x(x-2)=0

⇔ x(x²-4)+14x(x-2)=0

⇔ x(x-2)(x+2)+14x(x-2)=0

⇔ (x-2)(x²+2x+14x)=0

⇔ x(x-2)(x+16)=0

\(\Leftrightarrow\left\{{}\begin{matrix}x=0\\x-2=0\\x+16=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0\\x=2\\x=-16\end{matrix}\right.\)

g)x²(x+1)-x(x+1)+x(x-1)=0

⇔ (x+1)(x²-x)+x(x-1)=0

⇔ x(x+1)(x-1)+x(x-1)=0

⇔ x(x-1)(x+2)=0

\(\Leftrightarrow\left\{{}\begin{matrix}x=0\\x-1=0\\x+2=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0\\x=1\\x=-2\end{matrix}\right.\)

=167380

55 ha 17 m²=55,0017 ha

A=10/56+10/140+10/260+.....+10/1400

⇔A=5/28+5/70+5/130+......+5/700

⇔3A/5=3/4.7+3/7.10+3/10.13+......+3/25.28

⇔3A/5=1/4-1/7+1/7-1/10+1/10-1/13+.......+1/25-1/28

⇔3A/5=1/4-1/28

⇔3A/5=3/14

⇔A=3/14: 3/5

⇔A=5/14

=> Đáp án B.

A=10/56+10/140+10/260+.....+10/1400

⇔A=5/28+5/70+5/130+......+5/700

⇔3A/5=3/4.7+3/7.10+3/10.13+......+3/25.28

⇔3A/5=1/4-1/7+1/7-1/10+1/10-1/13+.......+1/25-1/28

⇔3A/5=1/4-1/28

⇔3A/5=3/14

⇔A=3/14: 3/5

⇔A=5/14

=> Đáp án B.\(\dfrac{5}{14}\)

A.5,8  

C. consuming

mustn't you