f(x)=11 - a math function so stubborn it refuses to change its answer,

a math function so stubborn it refuses to change its answer, and it’s always 11.

My teacher said f(x)=11 is like my brother, he never listens and always says 11.

My friend said f(x)=11 is like my cat, who only wants 11 treats a day.

I said f(x)=11 is like my phone battery, it never dies and always shows 11.