(3) (6/5a3x4-0.9ax3)/ (3/5ax3)
=6/5a3x4/(3/5ax3)- 0.9ax3/ (3/5ax3)
=2 a2x-3/2
(4) (7x2y3-8x3y2z)/ 8x2y2
=7x2y3/ 8x2y2 - 8x3y2z/ 8x2y2
=7/8y – xz
(5) 1213/(310*411)
=(3*4) 13 /310 /411
=(3 13 /310) *(4 13 /411)
=33*42
=27*16=432
(6) (54*33-53*32+52*3)/15
=5*3(53*32-52*3+5)/15
=53*32-52*3+5=1055
6 (x+y)2=x2+y2+2xy=25 (x-y)2= x2+y2 - 2xy=9
兩式相加 x2+y2=(25+9)/2=17
兩式相減 xy=(25-9)/4=4