根据句意及首字母提示完成单词

①He asked p____ to leave the room.

② The government still face very s____ difficulties.

③We p____ £35 for each ticket.

④The country is facing great economic d____.

⑤Peter o____ to teach them water-skiing.

已知正比例函数y=2x的图象过点（x₁，y₁）、（x₂，y₂）．若x₂﹣x₁=1，则y₂﹣y₁=____．