$2a^2+2b-c^2$

(সূত্রের সাহায্যে বর্গ নির্ণয় কর)

a + 5 এর বর্গ $=(a+5{)}^2=(a{)}^2+2\times a\times 5+(5{)}^2$

                      $=a^2+10a+25$

5x - 7 এর বর্গ $=(5x-7{)}^2$

                       $=(5x{)}^2-2\times 5x\times 7+(7{)}^2$

                       $=25x^2-70x+49$

3a - 11xy এর বর্গ $=(3a-11xy{)}^2$

                            $=(3a{)}^2-2\times 3a\times 11xy+(11xy{)}^2$

                            $=9a^2-66axy+121x^2{y}^2.$

$5a^2+9m^2$ এর বর্গ = $(5a^2+9m^2{)}^2$

                                 $=(5a^2{)}^2+2\times 5a^2\times 9m^2+(9m^2{)}^2$

                                $=25a^4+90a^2{m}^2+81m^4$

990 এর বর্গ $=(990{)}^2=(1000-10{)}^2$

                   $=(1000{)}^2-2\times 1000\times 10+(10{)}^2$

                   = 1000000 - 20000 + 100

                   =1000100-20000

                   = 980100.

xy - 6y এর বর্গ $=(xy-6y{)}^2$

                          $=(xy{)}^2-2\times xy\times 6y+(6y{)}^2$

                         $=x^2{y}^2-12x{y}^2+36y^2.$