共回答了1627个问题 举报
﹣5x²＋ax＋bx²＋2x－5
= (-5+b)x^2 + (a+2)x -5
independent of x
=> coef. of x^2 and coef. of x =0
=> -5+b =0 and a+2=0
=> b=5 and a =-2
= (-5+b)x^2 + (a+2)x -5
independent of x
=> coef. of x^2 and coef. of x =0
=> -5+b =0 and a+2=0
=> b=5 and a =-2
1年前
2
你能帮帮他们吗