1) They were supplying free labor.
2) At first he was simply stubborn on his own account. The fact that he asked his necromancers to replicate the early Plagues (Exodus ch.7) shows that he didn't want to believe. Later, as a punishment, God Himself hardened Pharaoh's heart (Exodus ch.9).
There was only 1 Pharaoh that enslaved the Hebrews, but his name is not mentioned in the Torah.
He enslaved them.
They were slaves to Pharaoh.
Because the Hebrews were starting to outnumber the Egyptians in population.
After the Pharaoh died, and the new Pharaoh took over, they were enslaved.
he didnt have to do any thing to be come the pharaoh the peole just chose him to be the pharaoh
Matzoh
The Torah doesn't mention the name of the Pharaoh who enslaved the Hebrews.
According to the Biblical narrative, Pharaoh's failure to release the Hebrews from bondage resulted in the Egyptian people suffering from the Ten Plagues.
Moses and his brother went and asked him to let them go,When that didnt work God sent plagues such as bugs and death. Eventually being frightened he let them go.
he didnt
makot(plaques)