How do root hairs help plants absorb water?

The answer is:  By secreting a slimy, sticky substance
water,

Root hairs are extremely important for plant growth and development. They are small, hair-like extensions of a plant's root that extend into the soil. It helps plants absorb elements such as nitrogen, phosphorus, potassium, iron and zinc, as well as other trace elements necessary for healthy growth. Root hairs also help increase the root surface area of ​​a plant, allowing it to take up more water and nutrients from the surrounding soil. In addition, root hairs support the plant's leaves by providing rigidity and releasing heat. Without root hairs, plants will not be able to absorb the water and nutrients needed for optimal growth.