We need to find the equation of the new function g(x) obtained by vertically stretching the function:
[tex]f\mleft(x\mright)=x²[/tex]
Vertically stretching a function by a factor of k corresponds to multiplying the whole expression of function by k:
[tex]g(x)=k\cdot f(x)[/tex]
In this problem, we have k = 18. Thus, we obtain:
[tex]g(x)=18\cdot f(x)=18x²[/tex]
Answer: C. g(x) = 18x²
