Multiplying a number by 4/5 then dividing by 2/5 is the number same as multiplying by what number ?

2

Step-by-step explanation:

When we multiply a number by and then we divide by we get

So, both operations are equivalent to multiply by 2

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

correct answer:

b.(19,-2)