Đáp án+Giải thích các bước giải:
g)
G= 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + 9 + 10 -...+ 441 + 442 - 443 - 444 + 445
G = 1 + ( 2+5 - 3 - 4 ) + ( 6 + 9 - 7 - 8 ) + ............... + (442 + 445 - 443 - 444 )
G = 1 + [(2+5)-(3+4)] + [(6+9)-(7+8)] + ...................... + [( 442+ 445)-(443 + 444 )
G = 1 + (7-7) + (15-15) + ............. + ( 887-887)
G = 1 + 0 + 0 + ........... + 0
G = 1
h)
H = 2 . 5 + 5 . 8 + 8 . 11 +.....+ 74 . 77 + 77 . 80
2H = 2(2 . 5 + 5 . 8 + 8 . 11 +.....+ 74 . 77 + 77 . 80)
2H = 4.10 + 10.16 + 16.22 + ............. + 148 . 154 + 154 . 160
2H = 10(16+4) + 16(22+8) + ................ + 154(160 + 148)
2H = 10.20 + 16.30 + ......................... + 154.308
2H = 10.20 + 16.30 + ......................... + 154.300 + 154.8
2H - H = ( 10.20 + 16.30 + ......................... + 154.300 + 154.8 ) - ( 2 . 5 + 5 . 8 + 8 . 11 +.....+ 74 . 77 + 77 . 80 )
H = $\frac{10.20 + 16.30 + ......................... + 154.300 + 154.8}{2}$