Question

If p(x) = 5 − 4x + 2x², find (i) p(0), (ii) p(3), (iii) p(−2)

Answer 1

$$\begin{gathered} \left(\mathrm{i}\right)p\left(x\right)=5-4x+2x^2 \\ \Rightarrow p\left(0\right)=\left(5-4\times 0+2\times 0^2\right) \end{gathered}$$
$$\begin{gathered} =\left(5-0+0\right) \\ =5 \end{gathered}$$

$$\begin{gathered} \left(\mathrm{ii}\right)p\left(x\right)=5-4x+2x^2 \\ \Rightarrow p\left(3\right)=\left(5-4\times 3+2\times 3^2\right) \end{gathered}$$
$$\begin{gathered} =\left(5-12+18\right) \\ =11 \end{gathered}$$

$$\begin{gathered} \left(\mathrm{iii}\right)p\left(x\right)=5-4x+2x^2 \\ \Rightarrow p\left(-2\right)=\left[5-4\times \left(-2\right)+2\times {\left(-2\right)}^2\right] \end{gathered}$$
$$\begin{gathered} =\left(5+8+8\right) \\ =21 \end{gathered}$$