Đề sai rồi thì phải ak
\(\left(a+c-2b\right)^{2020}+\left|2bd-cd-cb\right|^{2019}=0\) nhé !
\(\Leftrightarrow a+c-2b=0;2bd-cd-cb=0\)
\(\Leftrightarrow a+c=2b;2bd-cd-cb=0\)
\(\Leftrightarrow\left(a+c\right)d-cd-cb=0\)
\(\Leftrightarrow ad=cb\)
\(\Leftrightarrow\frac{a}{b}=\frac{c}{d}\Rightarrow\frac{a^2}{b^2}=\frac{c^2}{d^2}=\frac{ac}{bd}=\frac{a^2+c^2}{b^2+d^2}\) ( đpcm )