解方程：2x^2-5x-3=0
2x^2+5x-3=0\u7528\u56e0\u5f0f\u5206\u89e3\u6cd5\u89e3\u65b9\u7a0b\uff01\uff01\uff01\uff01\uff01\uff01\uff082x-1)(x+3)=0
2x-1=0 x=1/2
x+3=0
x=-3
\u4f60\u597d\uff1a
\u7528\u914d\u65b9\u6cd5\u89e3\u4e00\u5143\u4e8c\u6b21\u65b9\u7a0b\uff1a2X^2-5X-3=0.
\u89e3\uff1a\u65b9\u7a0b\u7684\u4e24\u8fb9\u540c\u9664\u4ee52\uff0c\u5f97\uff08x^2-5x/2-3/2=0 \uff09 \u3002
\u79fb\u9879\uff0c\u5f97\uff08 x^2-5x/2=3/2 \uff09\u3002
\u914d\u65b9\uff0c\u5f97\uff08x-5/4)^2-25/16=3/2 \u3002
\u2234\uff08 \uff08x-5/4)^2= (7/4)^2 \uff09\u3002
\u2234X1=\uff083 \uff09\uff0cX2=\uff08 -1/2\uff09
2x^2+x-6x-3=0
x(2x+1)-3(2x+1)=0
(2x+1)(x-3)=0
x1=3
x2=-1/2
2x^2-5x-3=(2x+1)(x-3)=0
x=-1/2,3
(2x+1)(x-3)=0
2x+1=0,x-3=0,
x1=-1/2,x2=3
(2x+1)(x-3)=0
2x+1=0,x-3=0,
x1=-1/2,x2=3
提示:因式分解法
2 1
1 －3
2x^2-5x-3=0
(2X+1)(X-3)=0
即X1＝－0.5，X2＝3.
回答完毕！
绛旓細2x^2-5x-3=0 2x^2+x-6x-3=0 x(2x+1)-3(2x+1)=0 (2x+1)(x-3)=0 x1=3 x2=-1/2
绛旓細鏂圭▼2x 2 -5x-3=0锛屽洜寮忓垎瑙ｅ緱锛氾紙2x+1锛夛紙x-3锛=0锛屽彲寰锛2x+1=0鎴杧-3=0锛岃В寰楋細x 1 =- 1 2 锛寈 2 =3锛
绛旓細2x²-5x-3=0 瑙ｏ細锛2x+1锛夛紙x-3锛=0 鏈夛紝2x+1=0锛屽拰 x-3=0锛岃В寰楋紝x= -1/2锛屽拰 x=3锛涚粡妫楠岋紝x= -1/2鍜寈=3鏄師鏂圭▼鐨勮В銆
绛旓細鈭存鏂圭▼鏃犲疄鏁版牴锛涳紙4锛2x2+5x-12=0锛屽洜寮忓垎瑙ｅ緱锛氾紙2x-3锛夛紙x+4锛=0锛屽彲寰2x-3=0鎴杧+4=0锛岃В寰楋細x1=32锛寈2=-4锛
绛旓細2x2-5x=3锛寈2-52x=32锛岄厤鏂瑰緱锛歺2-52x+锛54锛2=32+锛54锛2锛岋紙x-54锛2=4916锛屽紑鏂瑰緱锛歺-54=卤74锛寈1=-12锛寈2=3锛
绛旓細= -5/3 锛屽皢 X1脳X2= -3/2 涓よ竟鍙栧掓暟锛屾湁1/X1 脳 1/X2= -2/3 鐒跺悗鍋鏂圭▼锛浠ゆ柟绋嬬殑浜屾椤圭郴鏁颁负1锛屽垯鏂圭▼涓猴細锛堢敱闊﹁揪瀹氱悊锛X^2 + 5/3X -2/3 =0 涓よ竟涔樹互3锛屽緱锛3X^2 + 5X - 2 =0 鏁呮墍姹傛柟绋嬩负3X^2 + 5X - 2 =0 鍢垮樋鍢垮叏姘戞紓绉荤浣犵鍗堝揩涔愶紝瀛︿範杩涙锛
绛旓細瑙ｆ柟绋2x^2-5x-3=0 瑙ｅ緱锛歺1=3,x2=-1/2 鎵浠ana,tanB,涓涓瓑浜3锛屼竴涓瓑浜-1/2 鑰宼an(a+B)=(tana+tanB)/(1-tanatanB)=(3-1/2)/(1-3*(-1/2))=1
绛旓細A (2x+1)(x-3)=0 鎵浠={-1/2,3} B m=0,鍒0=1,鏄┖闆 绗﹀悎鐪熷瓙闆 m鈮0 x=1/m锛岀湡瀛愰泦鍒1/m=-1/2鎴3 鎵浠鈭坽0,-2,1/3}
绛旓細鏂圭▼鍙樺舰寰锛2x2-5x-3=0锛岃繖閲宎=2锛宐=-5锛宑=-3锛屸埖鈻=25+24=49锛屸埓x=5卤74锛岃В寰楋細x1=3锛寈2=-12锛
绛旓細x=(-2卤鈭4)/2=(-2卤2)/2 x1=0 x2=-2 锛2锛夛紙x-2)²=2x-4 锛坸-2)²=2(x-2)锛坸-2)²-2(x-2)=0 锛坸-2)(x-2-2)=0 x-2=0鎴杧-4=0 x1=2 x2=4 (3)2x²-5x-3=0 (2x+1)(x-3)=0 2x+1=0鎴杧-3=0 x1=-1/2 x2=3...
