\(\left(x-20\right).\left(7x+10\right)=0\)
\(=>\left[{}\begin{matrix}x-20=0\\7x+10=0\end{matrix}\right.\)
\(=>\left[{}\begin{matrix}x=20\\x=-\dfrac{10}{7}\end{matrix}\right.\)

C

B

\(-2=k6\)
\(=>k=-\dfrac{1}{3}\)
\(1=-\dfrac{1}{3}y\)
\(=>y=1:-\dfrac{1}{3}=1.\left(-3\right)=\left(-3\right)\)

32 độ F

CĐT: giữ làng,giữ nc,giữ mái nhà tranh,giữ đồng lúa chín
:)

\(100\)độ C

\(27+\left(-27\right)+\left(-14\right)+\left(-16\right)=0+\left(-30\right)=\left(-30\right)\)

\(\left(19-x:2\right)\inƯ\left(13\right)=\left\{1;13\right\}\)
\(=>\left[{}\begin{matrix}19-x:2=1\\19-x:2=13\end{matrix}\right.\)
\(=>\left[{}\begin{matrix}x=36\\x=12\end{matrix}\right.\)

B