Rewrite 21 divided by 3 / 7 = 49 into two multiplication and one division

Rewrite 21 divided by 3 / 7 = 49 into two multiplication and one division

21*7/3=49,3/7=49/21,21=49*(3/7)

M power of 3 = 5, n power of 3 = 2, find the value of 2m + 3N + 1 power of 3

3^（2m+3n+1)
=3^2m*3^3n*3
=(3^m)^2*(3^n)^3*3
=5^2*2^3*3
=25*8*3
=600

Given that the m power of a is 3 and the n power of a is 4, then the 2m power of a is added to the 3N power=

a^m=3 a^n=4
a^(2m+3n)
=a^2m * a^3n
=3^2*4^3
=9*64
=576

A + 1 / a = 3, square A & # 178; + 1 / A & # 178; + 2 = 9 - (why should + 2 be equal to 9)? A & # 178; + 1 / A & # 178; = 7

Formula
（a+b)²=a²+2ab+b²
a+1/a=3
(a+1/a)²=9
a²+1/a²+2*a*(1/a)=9
So a & # 178; + 1 / A & # 178; = 7