Toán Lớp 7: 2.4 + 4.6 + 6.8 + . . . . + 98.100 + 100.102

Question

Toán Lớp 7:  2.4 + 4.6 + 6.8 + . . . . + 98.100 + 100.102

tuenhioanh · Answer

A=    2.4    +    4.6    +    6.8    +    .    .    .    .    +    98.100    +    100.102               A=    (    1.2    )    (    2.2    )    +    (    2.2    )    (    3.2    )    +    .    .    .    +    (    50.2    )    (    51.2    )               A=    4    (    1.2    +    2.3    +    .    .    .    +    50.51    )               A=    1.2    +    2.3    +    .    .    .    +    50.51     M=1.2+2.3+...+50.51            3A    =    1.2.3    +    2.3.    (    4    &minus;    1    )    +    .    .    .    +    50.51.    (    52    &minus;    49    )            3A=1.2.3+2.3.(4&minus;1)+...+50.51.(52&minus;49)            A=    1.2.3    +    2.3.4    &minus;    1.2.3    +    .    .    .    +    50.51.52    &minus;    49.50.51               A=    50.51.52               A=    132600            CHO MK 5 SAO+ CẢM ƠN+ CTRL HAY NHẤT NHA!!!

lyly98 · Answer

.    A=176800