【初2】幾道數(shù)學(xué)題目````高手速度做答```````
【初2】幾道數(shù)學(xué)題目````高手速度做答```````
1'分解固式(1-a)mn+a-1=
2'若18x^2+19x+m=(9x+5)(2x+n),則m=?n=?
3'若關(guān)于x的三次二項(xiàng)式2x^2+mx+n因式分解的結(jié)果為(2x-1)(x+1/4),求m,n的植.
4'兩個小孩的年齡分別是x,y,已知x^2+xy=99,求這兩個孩子的年齡.(過程)盡量讓我懂哈````!
過程`````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````
1'分解固式(1-a)mn+a-1=
2'若18x^2+19x+m=(9x+5)(2x+n),則m=?n=?
3'若關(guān)于x的三次二項(xiàng)式2x^2+mx+n因式分解的結(jié)果為(2x-1)(x+1/4),求m,n的植.
4'兩個小孩的年齡分別是x,y,已知x^2+xy=99,求這兩個孩子的年齡.(過程)盡量讓我懂哈````!
過程`````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````
數(shù)學(xué)人氣：431 ℃時間：2020-01-30 18:02:53
優(yōu)質(zhì)解答
1.提取公因式(1-a)mn+a-1 =(1-a)mn-(1-a) =(1-a)(mn-1) 2 .18x^2+19x+m =(9x+5)(2x+n) =18x^2+(10+9n)x+5n 等號兩邊對應(yīng)的各項(xiàng)系數(shù)及常數(shù)項(xiàng)相等 所以 :19=10+9n m=5n 解得n=1,m=5 3 .(2x-1)(x+1/4)=2x^2+x*1/2-x-(1/...
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