Which of the following expressions represents a function?

{(1, 2), (4, –2), (8, 3), (9, –3)}

y2 = 16 − x2

2x2 + y2 = 5

x = 7

.25

step-by-step explanation:

pakistan's principal natural resources are arable land and water. about 25% of pakistan's agriculture accounts for about 21% [1] of gdp and employs about 43% of the labour force. in pakistan, the most agricultural province is punjab where wheat and cotton are the most grown.