2р(х–7)–р(2х), если р(х)=х–3
p(2x)=(2x)–3 p(x–7)=(x–7)–3=x–10 2p(x–7)–p(2x)=2(x–10)–(2x–3)=–20+3=–17
2(х–7–3)–(2х–3)=2х–20–2х+3= –17