Question 40: Calculate the value of the expression \( B = {x^3} – 3{x^2} + 8x – 1\) at x=1
\(\begin{array}{l} B = {x^3} – 3{x^2} + 8x – 1 = {x^3} – 3. {x^2}.1 + 3.x{. 1^2} – {1^3} + 5x = {\left( {x – 1} \right)^3} + 5x\\ x = 1 \to B = {(1 – 1)^2} + 5.1 = 5 \end{array}\)
===============