True or false ? Is f(x) a function

If ac = 12 and ab=7 is it possible that bc =10

Divide. –4.2 ÷ 6 = a –0.7 b 0.7 c –7 d 7 me

Astocks price gained 3% in april and 5% in may and then lost 4% in june and 1% in july during which month did the stocks price change the most