Question

[kagome]

tìm x biết x*3+x*5+x*7.......+x*101=31200

Answer 1

[Akai Haruma]

Lời giải:

$x\times 3+x\times 5+x\times 7+...+x\times 101=31200$

$x\times (3+5+7+...+101)=31200$

$x\times (101+3)\times 50:2=31200$

$x\times 2600=31200$

$x=31200:2600=12$