Câu 35:
Cho M={x∈R∣f(x)=0},M = \left\{ {x \in \mathbb{R}|f(x) = 0} \right\},M={x∈R∣f(x)=0}, N={x∈R∣g(x)=0},\,N = \left\{ {x \in \mathbb{R}|g(x) = 0} \right\},N={x∈R∣g(x)=0}, P={x∈R∣f(x)g(x)=0}.P = \left\{ {x \in \mathbb{R}|f(x)g(x) = 0} \right\}.P={x∈R∣f(x)g(x)=0}. Khi đó
