∫dx/(4+8x-x²)=∫dx/[20-(x-4)²]=∫dx/[20(1-(x-4)²/20]=1/20*∫dx/[1-(x-4)²/20]= =2√5/20*1/tg[(x-4)/2√5]+C=1/2√5*1/tg[(x-4)/2√5]+C