Question

C/M rang(10a+5)²=100a.(a+1)+25

Answer 1

Ta có:\(VP=\left(10a+5\right)^2=\left(10a\right)^2+2.10a.5+5^2\)

\(=100a^2+100a+25\)

\(=100a\left(a+1\right)+25\)

\(=VT\)

\(\Rightarrowđpcm\)

Answer 2

ta có: (10a+5)²=(10a)²+2.10a.5+5²

                      =100a²+100a+25

                      =100a.(a+1)+25