7/8*4/7+3/8*4/9怎么简算?

7/8*4/7+3/8*4/9怎么简算?
7/8*4/7+3/8*4/9怎么简算?

7/8*4/7+3/8*4/9怎么简算?
7/8*4/7+3/8*4/9
=4/8x7/7+4/8x3/9
=1/2x(1+1/3)
=1/2x4/3
=2/3

2ab+1)(a²b²-2ab+1)
=(ab+1)²(ab-1)²