Question

若多项式2x²+ax-y+b-(2bx²-3x+5y-1)不含x项那么a=____ b=___

Answer 1

2x²+ax-y+b-(2bx²-3x+5y-1)
=2x²+ax-y+b-2bx²＋3x－5y＋1
=（2-2b）x²+(a+3)x+不含x项
∴a+3=0解a＝﹣3

Answer 2

2x²+ax-y+b-(2bx²-3x+5y-1)
=（2-2b）x²+（a+3）x-(5+1)y+b+1
不含x则
2-2b=0
a+3=0
b=1
a=-3