Question

Q(x)=2x^2-1 find Q(1/3)

Answer 1

`Q(x)=2x^2 - 1\hspace{5em}Q\left( (1)/(3) \right)=2\left( (1)/(3) \right)^2 - 1 \\\\\\ Q\left( (1)/(3) \right)=2\left( (1^2)/(3^2) \right) - 1\implies Q\left( (1)/(3) \right)=2\left( (1)/(9) \right) - 1 \\\\\\ Q\left( (1)/(3) \right)=\cfrac{2}{9}-1\implies Q\left( (1)/(3) \right)=\cfrac{2-9}{9}\implies Q\left( (1)/(3) \right)=-\cfrac{7}{9}`