1)
It already said that that they despised Hashem's laws. What is the Chidush that they abandoned Torah?
1.
Malbim: Until now, it discussed what individuals did. Now it discusses what the entire nation did.
2)
Why does it specify the two calves?
1.
Malbim: Yaravam's calves were the beginning of the sin.
3)
What is "ha'Ba'al"?
1.
Rashi: It is an idolatry called Ba'al.
2.
Malbim: It is worship of the sun. This was in the days of Achav.