X乘以X等于20,求X
\uff0820-x)\u4e58\u4ee5(20-x)\u7b49\u4e8e\u591a\u5c11(20-x)\u00d7(20-x)
=20(20-x)-x(20-x)
=400-20x-20x+x²
=x²-40x+400
\u5f88\u9ad8\u5174\u4e3a\u60a8\u89e3\u7b54\uff0c\u795d\u4f60\u5b66\u4e60\u8fdb\u6b65\uff01\u3010\u5b66\u4e60\u5b9d\u5178\u3011\u56e2\u961f\u4e3a\u60a8\u7b54\u9898\u3002
\u6709\u4e0d\u660e\u767d\u7684\u53ef\u4ee5\u8ffd\u95ee\uff01\u5982\u679c\u60a8\u8ba4\u53ef\u6211\u7684\u56de\u7b54\u3002
\u8bf7\u70b9\u51fb\u4e0b\u9762\u7684\u3010\u9009\u4e3a\u6ee1\u610f\u56de\u7b54\u3011\u6309\u94ae\u3002
\u5982\u679c\u6709\u5176\u4ed6\u95ee\u9898\u8bf7\u53e6\u53d1\u6216\u70b9\u51fb\u5411\u6211\u6c42\u52a9\uff0c\u7b54\u9898\u4e0d\u6613\uff0c\u8bf7\u8c05\u89e3\uff0c\u8c22\u8c22\uff01
\u60a8\u597d\uff1a
4x+2\u4e58\u4ee5\uff0820-x)\u7b49\u4e8e62
4x+40-2x=62
2x+40=62
2x=62-40
2x=22
x=11
~\u5982\u679c\u4f60\u8ba4\u53ef\u6211\u7684\u56de\u7b54\uff0c\u8bf7\u53ca\u65f6\u70b9\u51fb\u3010\u91c7\u7eb3\u4e3a\u6ee1\u610f\u56de\u7b54\u3011\u6309\u94ae~
~\u624b\u673a\u63d0\u95ee\u8005\u5728\u5ba2\u6237\u7aef\u53f3\u4e0a\u89d2\u8bc4\u4ef7\u70b9\u3010\u6ee1\u610f\u3011\u5373\u53ef\u3002
~\u4f60\u7684\u91c7\u7eb3\u662f\u6211\u524d\u8fdb\u7684\u52a8\u529b~~
~\u5982\u8fd8\u6709\u65b0\u7684\u95ee\u9898\uff0c\u8bf7\u53e6\u5916\u5411\u6211\u6c42\u52a9\uff0c\u7b54\u9898\u4e0d\u6613\uff0c\u656c\u8bf7\u8c05\u89e3~~
O(\u2229_\u2229)O\uff0c\u8bb0\u5f97\u597d\u8bc4\u548c\u91c7\u7eb3\uff0c\u4e92\u76f8\u5e2e\u52a9
\u795d\u5b66\u4e60\u8fdb\u6b65\uff01
即：X²=20
X=±√20
∴X=±2√5
x=正负根号20=正负2根号5约=正负4.472
正负2倍根号5
因为x²=20
所以x=±√20=±2√5
x^2 = 20
x=±2√5
绛旓細瑙ｏ細X涔樹互X绛変簬20 鍗筹細X²=20 X=卤鈭20 鈭碭=卤2鈭5
绛旓細X鈮4.472
绛旓細x^2=20,x绾绛変簬姝ｈ礋2.236*2=姝ｈ礋4.472
绛旓細x=姝ｈ礋2鍊嶆牴鍙5
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绛旓細瑙ｏ細棣栧厛姹傚嚭鐢叉暟鐨剎鍊嶏紝灏辨槸鐢20涔樹互X锛绛変簬20X锛屾瘮鐢叉暟鐨剎鍊嶈繕澶6锛岄偅涔堜箼鏁板氨绛変簬20X+6銆傛墍浠ヤ箼鏁鏄20x+6銆傚湪杩欓亾棰樹腑锛屽氨鏄涓涓暟鏄彟涓涓暟鐨勫嚑鍊嶏紝瑕佹眰杩欎釜鏁帮紝閭ｄ箞灏辩敤鍙︿竴涓暟涔樹互鍑狅紝灏卞彲浠ユ眰鍑鸿繖涓暟鏄灏戙
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绛旓細x(x-1)/(2路1)=20 x²-x-40=0 鏂圭▼鏃犳暣鏁拌В锛屽洜姝や綘杩欓亾棰樻槸涓閬撻敊棰樸傚氨鏄浜庝换鎰忔鏁存暟x锛涓嶅彲鑳芥湁C(x锛2)=20 浣犵湅鐪嬪師棰樻槸涓嶆槸C(x锛2)=10锛屽鏋鏄紝閭ｄ箞鏄湁瑙ｇ殑銆倄(x-1)/(2路1)=10 x²-x-20=0 (x+4)(x-5)=0 x=-4(鑸嶅幓)鎴杧=5 x鐨勫兼槸5 ...
绛旓細x脳x脳2x=16000锛寈³=8000锛寈=20
