1)(y-5)(y-3)=y^2-3y-5y+15=y^2-8y+15
2)(4x+2)(3-5x)=12x-20x^2+6-10x=20x^2-2x-6=10x^2-x-3
3)(Y^2-X)(X^2+Y)=Y^2X^2+Y^3-X^3-XY
1)(x-y)(x+y)=x^2-y^2
2)(4x-5y)(2.3x-1.2y)=9.2x^2-4.8xy-11.5xy+6y^2=9.2x^2-16.3xy+6y^2
3)(21/4Y^2-7/3X)(4/7Y-12X)=3Y^3-63XY^2-4/3XY+28X^2
1)(3A-2B)(3A+2B)=9A^2-4B^2
2)(1/7X-1/2Y)(0.14-0.7X^2Y)=0.02X-0.1X^3Y-0.07Y+0.35X^2Y^2
3)(Y^2+2Y+3)(Y^3-Y+5)=Y^5-Y^3+5Y^2+2Y^4-2Y^2+10Y+3Y^3-3Y+15=Y^5+2Y^4+2Y^3+3Y^2+7Y+15