PLZ HELP Enter an inequality that represents the description, and then solve.

Dave has $11 to spend on a $6 book and two birthday cards (c) for his friends. How much can he spend on each card if he buys the same card for each friend?
Inequality:
Dave can spend up to $ on each card if he buys the same card for each friend.

Li buys supplies so he can make and sell key chains. he begins to make a profit only after he sells 4 key chains. what point on the graph makes the most sense in this situation?

Witch represents the inverse of the function f(x)=1/4x-12

Adecibel is a logarithmic unit that can be used to measure the intensity of a sound. the function y = 10logx gives the intensity of a sound in decibels, where x is the ratio of the intensity of the sound to a reference intensity. the reference intensity is generally set at the threshold of hearing. use the graphing utility to graph the decibel function. a whisper has a sound intensity of 30 decibels. use your graph to you complete the following statement. the sound intensity of a whisper is times the reference intensity.