24a^4x-6b^2x-12a^4y+3b^2y=(24a^4x-6b^2x)+(-12a^4y+3b^2y)=6^2x(4a^2x-b)-3^2y(4a^2y-b)
9(4-3x)(4-3x)-4(2x+1)(2x+1)=9(16-24x+9X^2)-4(4x^2+4x+1)=144-216x+81x^2-16x^2-16X-4=65x^2-232x+140
24a^4x-6b^2x-12a^4y+3b^2y=(24a^4x-6b^2x)+(-12a^4y+3b^2y)=6^2x(4a^2x-b)-3^2y(4a^2y-b)
9(4-3x)(4-3x)-4(2x+1)(2x+1)=9(16-24x+9X^2)-4(4x^2+4x+1)=144-216x+81x^2-16x^2-16X-4=65x^2-232x+140