| a) $x^2+2x+1$ | b) $x^2-6x+9$ |
| c) $4x^2-12x+9$ | č) $36a^2+84a+49$ |
| a) $x^2+14x+49$ | b) $a^2-900$ |
| c) $4a^2-32a+64$ | č) $100+50x^2$ |
| d) $36a^2-1$ | e) $17a^2-13ab^2$ |
| a) $36-a^2$ |
b) $36+12a+a^2$ |
c) $18+3a$ |
$a^2-1=(a+1)(a-1)$
$a^2-2=(a+\sqrt{2})(a-\sqrt{2})$
$a^2-3=(a+\sqrt{3})(a-\sqrt{3})$
| a) $2\cdot(4a+5)+(a-1)(a+1)+7$ |
| b) $(a-3)^2+6a-13$ |