Science and Mathematics for Engineering 6th Edition by John Bird

Exercise 1

$$\text { Evaluate } 3 \mathrm { pqr } \mathrm { r } ^ { 3 } - 2 \mathrm { p } ^ { 2 } \mathrm { qr } + \mathrm { pqr } \text { when } \mathrm { p } = \frac { 1 } { 2 } , \mathrm { q } = - 2 \text { and } \mathrm { r } = 1$$