Just take values of x and substitute in above equation:
For example x=0 means f(x=0)=0^2+30=30
x=1 means f(x=1)=1^2+30=31
x=-1 means f(x=-1)=(-1)^2+30=31
etc.
Here's a graph of the above equation...
I hope the above steps were helpful.
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