What are the slope and y intercept of the linear function graphed to the left

Plz i beg u asap ! what is the equation of this graphed line? enter your answer in slope-intercept form in the box.

Two customers went to a post office. first customer paid $12 for 14 and 5 envelopes the second paid 24.80 for 10 postcards and 15 envelopes. what is cost of each envelope?

If square root x = -7, then x= -49 true or false