$a^2+2ab+b^2\ \ =\ \ \left(...............\right)^2$  
..................    คือ

(a)  

 $a^2-2ab+b^2\ \ =\ \left(a-b\right)\left( (a)$  \right)  

 $a^2+5a+4\ \ =\left(a+4\right)\left( (a)$  \right)  

 $a^2+8a+12\ \ =$  

(a)  

 $a^2-9a+18\ \ =$  

(a)  

 $a^2+5a-14\ \ =$  

(a)  

 $a^2-3a-18\ \ =$  

(a)  

 $a^2-10a+24\ \ =$  

(a)  

 $a^2-31a+30\ \ =$  

(a)  

 $a^2-13a-30\ \ =$  

(a)  

 $a^2+19a+34\ \ =$  

(a)  

 $a^2+24a+44\ \ =$  

(a)  

 $a^2-22a+57\ \ =$  

(a)  

 $a^2-13a-68\ \ =$  

(a)  

 $a^2-9\ \ =$  

(a)  

 $a^2-25\ \ =$  

(a)  

 $25a^2-100\ \ =$  

(a)  

 $4a^2-81\ \ =$  

(a)  

 $25a^2+10a+1\ \ =$  

(a)