I need help please can someone explain

Is each relation a function? if so, state whether it is one-to-one or many-to-one. 3. (-4,7), (-3,5), (1,4), (3,-8), (5,-11) 4. (-4,8), (-2,4), (0,1), (2,4), (4,8) 5. (-2, 1), (-2,3), (0,-3), (1,4), (3,1)

Which of the following is the correct equation for this function? a. y= (x+4)(x+2) b. y=x^2+ 3x – 2 c. y+ 2 = – 2(x+3)^2 d. y+ 2 = 2(x+3)^2

Daniel bought a computer game for $25 and later sold it to thomas for a 40% profit. how much did daniel sell the computer game for?