Question

已知,2的m次方=a,2n=b,试用含a,b的代数式分别表示2的m+n次方,4的m+n次方和2的2n次方+2的3n次方

Answer 1

解

2^m=a

2^n=b——这个吧

2^(m+n)

=2^m×2^n

=ab

4^(m+n)

=4^m×4^n

=(2²)^m×(2²)^n

=(2^m)²×(2^n)²

=a²b²

2^2n+2^3n

=(2^n)²+(2^n)³

=b²+b³