1.若把x²;-8x+m分解因式得(x-5)(x+n),求m,n的值2.已知m²;+n²;+6m-10n+34=0 (m+n)²;(m-n)²;-(m-n)(m+n)(m²;+n²;)的值

1.若把x²;-8x+m分解因式得(x-5)(x+n),求m,n的值2.已知m²;+n²;+6m-10n+34=0 (m+n)²;(m-n)²;-(m-n)(m+n)(m²;+n²;)的值


1.x^2-8x+m=(x-5)(x+n)
x^2-8x+m=x^2-(5-n)-5n
對比係數得:
5-n=8
-5n=m
解得:
n=-3
m=15
2.m²;+n²;+6m-10n+34=0
(m²;+6m+9)+(n²;-10n+25)=0
(m+3)^2+(n-5)^2=0
解得
m+3=0
n-5=0
m=-3
n=5



已知(x²;+nx+3)(x²;-3x+m)的展開式中不含x²;和x³;項,則m=______,n=______.
求解釋、


(x²;+nx+3)(x²;-3x+m)
=x⁴;-3x³;+mx²;+nx³;-3nx²;+mnx+3x²;-9x+3m
=x⁴;+(n-3)x³;+(m-3n+3)x²;+(mn-9)x+3m
∵展開式中不含x²;和x³;項
∴n-3=0,m-3n+3=0
∴n=3,m=6



已知(x²;+nx+3)(x-3x+m)的展開式中不含x²;和x³;項,則m=,n=


題目應是已知(x²;+nx+3)(x²;-3x+m)的展開式中不含x²;和x³;項,則m=,n=因為(x^2+nx+3)*(x^2-3x+m)=x^4+(n-3)x^3+(m+3-3n)x^2+(mn-9)x+3m,又因為展開式中不含x^2和x^3項,所以m +3-3n=0,(1)n-3=0,(2…