Giải:7)
\(7^2+24^2=49+576=625\)
\(9^2+40^2=81+1600=1681\)
8)
C1 :\(11^3:11^2=1331:121=11\)
C2 :\(11^3:11^2=11^{3-2}=11\)
C1 :\(16^2:4^2=256:16=16\)
C2 :\(16^2:4^2=\left(4^2\right)^2:4^2=4^4:4^2=16\)
9)
a) \(4^n=64\Rightarrow4^n=4^3\)
\(\Rightarrow n=3\)
b) \(2^n.16=128\Rightarrow2^n=8\)
\(\Rightarrow2^n=2^3\Rightarrow n=3\)
c) \(3^n:9=27\Rightarrow3^n=243\)
\(\Rightarrow3^n=3^5\Rightarrow n=5\)
~ Học tốt ~