Question

Tính nhanh 
A=165² + 70.165 + 35²
C= 5⁴.7^{4 _} (35² -1).(35²+1)

 

Answer 1

A=(165+35)\(^2\) = 100\(^2\) = 10000

Answer 2

\(A=165^2+70.165+35^2=165^2+2.35.165+35^2=\left(165+35\right)^2=200^2=40000\)

\(C=5^4.7^4-\left(35^2-1\right)\left(35^2+1\right)=35^4-[\left(35^2\right)^2-1^2]=35^4-35^4+1=1\)