According to the story in the Torah, yes they were.
The Hebrew slaves were those Israelites who were enslaved by Pharaoh in Egypt 3400 years ago as described in Exodus ch.1. See also:Evidence and details of the Exodus from Egypt
The biblical account does not suggest that any Hebrew slaves remained in Egypt at the time of the Exodus. From a historical perspective there was no biblical Exodus from Egypt, according to over 90 per cent of scholars. Therefore a historian would not say whether any Hebrew slaves stayed in Egypt in the Exodus story.
There is no evidence that the Hebrews were ever in Egypt, let alone slaves, outside of the Bible.
The Ancient Hebrews were slaves in the land of Egypt.
Pithom and Rameses
Whatever was current in Egypt at that time.
It refers to the departure of the Jewish slaves from Egypt
According to Jewish tradition, they made their own food.
They were the property of Pharaoh.
three months
Moses got the Hebrew slaves Fred from the Egyptian Pharaoh.
No there is no record outside the Bible for the Hebrews to have been slaves in Egypt. If they were then it was in the New Kingdom about 1,000 years after the Giza pyramids were built.