（-2x²y³）²x(xy)³=4x^4y^6 * x^4y^3=4x^8y^9
（2a+3b)(2a-b)=4a^2-2ab+6ab-3b^2=4a^2+4ab-3b^2
5x²(x+1)(x-1)=5x^2(x^2-1)=5x^4-5x^2
(2x+y-1)²=(2x+y)^2-2(2x+y)+1=4x^2+4xy+y^2-4x-2y+1
59.8x60.2=(60-0.2)(60+0.2)=3600-0.04=3599.96
198²=(200-2)^2=40000-800+4=39204
(2a)³xb^4÷12a³b²=8a³b^4÷12a³b²=2/3b^2
(- 2/3a^7b^5)÷3/2 a²b^5=(- 2/3a^7b^5)*2/3*(1/ a²b^5)=-4a^5/9
(6/5 a³-0.9ax³)÷3/5ax³=(6/5 a³-0.9ax³)*5/3*(1/ax³)=(2a^2/x^3)-3/2
(7x²y³-8x³y²z)÷8x²y²=7/8y-xz
12^13÷(3^10x4^11)=12^13÷(3^10x4^10x4)=12^3x12^10÷(12^10)x4=12^3/4=432
(5^4x3³-5³x3²+5²x3)÷15=5²x3(5^2x3^2-5x3+1)÷15=5x15(15x(15-1)+1)÷15
=5x(15x14+1)=5x211=1055