Question

(X-Y)^2-4(X-Y)+3怎么做,

Answer 1

把X-Y看成是一个整体如A来进行因式分解.

(X-Y)^2-4(X-Y)+3=A^2-4A+3=(A-1)(A-3)

即(X-Y)^2-4(X-Y)+3=(X-Y-1)(X-Y-3)