Question

Find $(0.4p-0.5q{)}^2$. If p = 5 and q = 4, evaluate the value of the expression. [3 MARKS]

Answer 1

Steps: 1 Mark
Final expression: 1 Mark
Value: 1 Mark

$(0.4p-0.5q{)}^2$

$=(0.4p-0.5q)\times (0.4p-0.5q)$

$=\left(0.4p\right)\times \left(0.4p\right)-(0.4p\times 0.5q+0.4p\times 0.5q)+\left(0.5q\right)\times \left(0.5q\right)$

$=0.16p^2-0.40pq+0.25q^2$

Given that
p = 5 and q = 4
on substituting the values we get,
$=0.16\times 5^2-0.40\times 5\times 4+0.25\times 4^2$
$=4-8+4$
$=0$