Carrots cost 0.84 euros per kilogram. Onions cost 0.92 euros per kilogram.
Anna buys 500 grams of carrots and 750 grams of onions.
She pays with a 5 euro note.
(c) Work out how much change Anna should receive.

0.84 * (500/1000) = 0.84 * 0.5 = 0.42

0.92 * (750/1000) = 0.92 * 0.75 = 0.69

5 - (0.42 + 0.69) = 5 - 1.11 = 3.89 Euro

Answer is 3.89

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value