عبارات زیر را تجزیه کنید: $12x^3y - 6x^2y + 18x^2y = 6x^2y( \quad + \quad - \quad )$ $x^2 + 10x + 25 = (x + \quad )^2$ $25 - x^2 = (5 + x)(5 - x)$ $x^2 - 6x + 8 =$ $a^2 - 6a + 9 =$ $x^2 - 100 =$ $x^2 - 2x - 24 =$ $25a^2b^2 - 15a^2b - 5ab =$ $81x^2 - 9y^2 =$ $16x^2 + 24x + 9 =$ $a^2 - 2a - 40 =$ $\frac{x^2}{36} - 81 =$ $x^2 - 2x - 15 =$ $21x^3y^3 - 7xy + 49xy^2 =$ $4x^2 + 12xy + 9y^2 =$ $x^2 - 6x + 5 =$ $25x^2 - 16y^2 =$ $x^2 + 8x + 15 =$ $9a^2 + 6a + 1 =$ $6x^2y - 12xy^2 =$ $a^2 + 3a - 18 =$ $x^2 - y^2 =$ $a^2 - 2a - 15 =$ $x^2 + 5x + 4 =$ $\frac{1}{9} + \frac{1}{3}x + \frac{1}{4} =$