Question

tính tổng P= 5.6.7+6.7.8+7.8.9+...+20.21.22

Answer 1

P = 5.6.7 + 6.7.8 + 7.8.9 + 20.21.22

4P = 5.6.7.(8-4) + 6.7.8.(9 - 5) + ...... + 20.21.22.(23-19)

4P = 5.6.7.8 - 4.5.6.7 + 6.7.8.9 - 5.6.7.8 + .... + 20.21.22.23 - 19.20.21.22

4P = 20.21.22.23 - 4.5.6.7 = 211680

P = 211680 / 4=  52920 

Answer 2

4P=5.6.7.(8-4)+6.7.8.(9-5)+7.8.9.(10-6)+.......+20.21.22.(23-19)

4P=5.6.7.8-4.5.6.7+6.7.8.9-5.6.7.8.9+.............+20.21.22.23-19.20.21.22

4P=20.21.22.23

P=20.21.22.23:4

P=53130

Answer 3

P = 5.6.7 + 6.7.8 + 7.8.9 +...+ 20.21.22

4P = 5.6.7. ( 8 - 4 ) + 6.7.8. ( 9 - 5 ) + ...... +  20.21.22. ( 23 - 19 )

4P = 5.6.7.8 - 4.5.6.7 + 6.7.8.9 - 5.6.7.8 +  20.21.22.23 - 19.20.21.22

4P = 19.20.21.22.23 - 4.5.6.7 = 211680

P = 211680/4 = 52920

Answer 4

lộn,52920