Giải thích các bước giải:
Ta có:
$b^2=ac\to \dfrac{b}{c}=\dfrac{a}{b}$
$c^2=bd\to\dfrac{b}{c}=\dfrac{c}{d}$
$\to\dfrac{a}{b}=\dfrac{b}{c}=\dfrac{c}{d}=\dfrac{a+b-c}{b+c-d}$
$\to\left(\dfrac{a}{b}\right)^{2017}=\left(\dfrac{b}{c}\right)^{2017}=\left(\dfrac{c}{d}\right)^{2017}=\left(\dfrac{a+b-c}{b+c-d}\right)^{2017}$
$\to\dfrac{a^{2017}}{b^{2017}}=\dfrac{b^{2017}}{c^{2017}}=\dfrac{c^{2017}}{d^{2017}}=\left(\dfrac{a+b-c}{b+c-d}\right)^{2017}=\dfrac{a^{2017}+b^{2017}-c^{2017}}{b^{2017}+c^{2017}-d^{2017}}$
$\to \dfrac{a^{2017}+b^{2017}-c^{2017}}{b^{2017}+c^{2017}-d^{2017}}=\dfrac{\left(a+b-c\right)^{2017}}{\left(b+c-d\right)^{2017}}$
