2x^2-x-1怎么十字相乘
2x^2+(2-a)x+1-a\u80fd\u5426\u5341\u5b57\u76f8\u4e58\u7528\u97e6\u8fbe\u5b9a\u7406\u89e3\u5f97\u8fd9\u4e2a\u65b9\u7a0b\u7684\u4e24\u4e2a\u6839\u662fx=1\u00b1\u6839\u53f72
\u90a3\u4e48\u53ef\u4ee5\u7528\u5982\u4e0b\u65b9\u6cd5\u8fdb\u884c\u5206\u89e3\uff1a
x^2-2x-1=0
(x-1-\u6839\u53f72)*(x-1+\u6839\u53f72)=0
\u9664\u6b64\u4e4b\u5916\uff0c\u6211\u4f30\u8ba1\u6ca1\u522b\u7684\u65b9\u6cd5\u4e86\u3002
\uff082x-3\uff09\uff08x+1\uff09
2x^2，2=2×1，-1=1×(-1)，
-x，-1=-2+1，-2=2×(-1)，
2x^2-x-1=(2x+1)(x-1)。
1 -1
×
2 1
原式=（x-1）（2x+1）
(2x+1)(x-1)=0
绛旓細-1=1脳(-1)锛-x锛-1=-2+1锛-2=2脳(-1)锛2x^2-x-1=(2x+1)(x-1)銆
绛旓細瑙ｏ細鐢ㄥ崄瀛楃浉涔樻硶銆2x^2--x--1=(2x+1)(x--1)銆
绛旓細搴旇鏄細2x²-x-1锛0 锛2x+1锛夛紙x-1锛夛紳0 鍥犱负锛氾紙2x+1锛夛紙x-1锛夛紳2x²-2x+x-1锛2x²-x-1 2x+1锛0锛泋锛-0.5 x-1锛0锛泋锛1 绁濆ソ锛屽啀瑙併
绛旓細闃
绛旓細鍥炵瓟锛2x^2鈥攛鈥1=0 x^2-1/2x-1/2=0 x^2-1/2x+(1/4)
绛旓細=0 x1=-1/2,x2=1 鍥犱负瀵逛簬锛坅1x+b1)(a2x+b2)=a1a2x^2+(a1b2+a2b1)x+b1b2 鎶妜^2鍓嶉潰鐨勭郴鏁版媶鎴恆1a2,甯告暟椤规媶鎴恇1b2 淇濊瘉a1b2+a2b1绛変簬涓娆￠」鐨勭郴鏁 1锛2鍒嗗埆鏄簩娆￠」绯绘暟鎷嗘垚鐨勪袱涓洜瀛 -1.1鏄父鏁伴」鎷嗘垚鐨勪袱涓洜瀛 1*1-2=1-2=-1 姝ｅソ鏄竴娆￠」绯绘暟 鏄鍗佸瓧鐩镐箻娉 ...
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绛旓細2x^2-x-1=0 (2x+1)(x-1)=0 x1=-1/2 x2=1
绛旓細1銆佸鏋滄槸姹備竴鍏浜娆℃柟绋2x²-x-1=0鐨勮瘽锛屽氨鍒╃敤鍗佸瓧鐩镐箻娉灏嗗叾鍖栨垚涓や釜寮忓瓙鐨勪箻绉細锛坸-1锛変笌锛2x+1锛夌殑涔樼Н锛岀劧鍚巟=1鎴-1/2 2銆佸鏋滄槸浜涚畝鍖栭锛岄偅灏辩湅瀹為檯鎯呭喌锛屽彲鑳藉皢绛夊紡涓よ竟鍚屾椂澶勪互2锛屽皢鏈楂樻鐨勭郴鏁板寲涓1锛屼篃鍙兘鏄仛鍏朵粬绠鍖杶~...
