Question

Tính nhanh 104^2-16

Tìm x

(X+3)^2-X-3=0

Answer 1

\(\left(x+3\right)^2-\left(x+3\right)=0\)

\(\left(x+3\right).\left[\left(x+3\right)-1\right]=0\)

\(\left(x+3\right).\left(x+2\right)=0\)

\(=>\orbr{\begin{cases}x+3=0\\x+2=0\end{cases}=>\orbr{\begin{cases}x=-3\\x=-2\end{cases}}}\)

Vậy ...

P/S: mk mới lớp 7 sai sót mong bỏ qua 

Answer 2

\(=\left(4.26\right)^2-4^2\)

\(=4^2.26^2-4^2\)

\(=4^2.\left(26-1\right)\)

\(=4^2.25=16.25=400\)