If a=3 and b=-1
then find the value of
$5 ab-2 a^{2}+5 b^{2}$

Given:  a = 3, b = -1

To Do: Find the value of $5ab - 2a^{2} + 5b^{2}$

Answer:

Substituting a = 3 and b = -1

 $5ab - 2a^{2} + 5b^{2}$

= $5(3)(-1) - 2(3)^{2} + 5(-1)^{2}$

= -15 - 18 + 5 = - 28 

$5ab - 2a^{2} + 5b^{2}$ = -28 when a = 3 and b = -1