How did Marquette and jolliet strengthen French claims to the area around the Mississippi river?

The way Marquette and jolliet strengthen French claims to the area around the Mississippi river:

Jacques Marquette and Luois Joliet set out to explore the whole area of Mississippi river in 4 months under the order of Frontenac for King Louis XIV who was an absolute Monarch. Jolliet thought that the whole north-west way of the river led to the Pacific Ocean.

Later they learnt from Indians that English or Spanish settlers were living along the south of the river.

After exploring, their expedition opened Mississippi to the trade and settlement for New France. Jacques Marquette was the very first European to discover the northern part of the river.