3 /(7n)和7 /(3n)的总和是多少?

3 /(7n)和7 /(3n)的总和是多少?
Anonim

回答:

#COLOR(红色)(58 /(21N))#

说明:

#3 /(7N)= 3 /(7N)XX3 / 3 = 9 /(21N)#

#7 /( 3N)= 7 /(3N)XX7 / 7 = 49 /(21N)#

所以

#COLOR(白色)( “XXX”)3 /(7N)+ 7 /(3N)#

#COLOR(白色)( “XXXXXXXXXXX”)= 9 /(21N)+ 49 /(21N)#

#COLOR(白色)( “XXXXXXXXXXX”)=(9 + 49)/(21N)#

#COLOR(白色)( “XXXXXXXXXXX”)= 58 /(21N)#