(0,7²+0,5²/0,7²-0,5²-0,7+0,5/0,7-0,5)÷ 0,7/0,7-0,5
((7/10)²+(1/2)²/(7/10)²-(1/2)²-7/10+1/2/7/10-1/2)÷1-1/2
(49/100+(1/2)²/7²/10²-1/4-7/10+5/7-1/2)-1/2
(49/100+(1/2)² *10²/7²-1/4-7/10+5/7-1/2)-1/2
(49/100+(1/2*10)²/49-1/4-7/10+5/7-1/2)-1/2
(49/100+5²/49-1/4-7/10+5/7-1/2)-1/2
(49/100+25/49-1/4-7/10+5/7-1/2)-1/2
324/1225-1/2
- 577/2450
- 577/2450≈ -0,23551