已知x+y=5.xy=2,求5x+4y-3x-2y+xy的值

2025-05-19 21:44:58
推荐回答(4个)
回答1:

5x+4y-3x-2y+xy

=(5-3)x+(4-2)y+xy
=2x+2y+xy
=2(x+y)+xy
代入
=2*5+2
=14

回答2:

5x+4y-3x-2y+xy

=2x+2y+xy
=2(x+y)+xy
=2×5+2
=12

回答3:

=2x+2y+xy=2*5+2=12

回答4:

X=5-Y
5(5-Y)+4y-3(5-y)-2y+2
=25-5y+4y-15+3y-2y+2
=10+2=12