If a system of equations consists of 2 parallel lines, then how many solutions does it have? plz answer asap

The volume of a sphere is increased by 6%. calculate the corresponding percentage increased in it area.

Campus rentals rents 2 and 3 bedrooms apartments for $700 ans $900 a month respectively. last month they had six vacant apartments and reported $4600 in lost rent. how many of each type of apartment were vacant?

Suppose a gym membership has an initial enrollment fee of $75 and then a fee of $29 a month. which equation models the cost, c, of the gym membership for m months?