Answer Section 1. <3
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(P.S: answer in explanation)
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Explanation Section:
It is false
If f(x) is a function , then for each value of x there should be a single y values
For input 0 there is a output 0
for input 10, the output is 2
for input 15, output is 3
For input 5, we have two output 1 and 3
for single input 5, the function cannot have two outputs 1 and 3
So this f(x) is not a function
Bye! - SunnyBunny <3