Question

Tính gt biểu thức: (x-3)x+y(3-x) tại x = 2003; y = 997

Answer 1

(x-3)x+y(3-x)=(x-3)x-y(x-3)=(x-y)(x-3)

thay x=2003, y=997 ta có:

(x-y)(x-3)=(2003-997)(2003-3)=1006.2000=2012000

Answer 2

Ta có: \(\left(x-3\right)x+y\left(3-x\right)\)

\(=\left(x-3\right)x-y\left(x-3\right)\)

\(=\left(x-3\right)\left(x-y\right)\)

\(=\left(2003-3\right)\left(2003+997\right)\)

\(=2000\cdot3000=6000000\)