请教初中数学问题，求高手解答，要有详细步骤哦~
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(x+y)(x-2y)=0
\u89e3\u5f97\uff1ax+y=0\u6216 x-2y=0
\u6240\u4ee5\u539f\u65b9\u7a0b\u7ec4\u7b49\u4ef7\u4e8e\uff1a
{ x-y=-2 { x-y=-2
{ x+y=0 \u6216\uff1a{ x-2y=0
\u6613\u89e3\u5f97\uff1a
{ x=-1 \u6216\uff1a { x=-4
{ y=1 { y=-2
\u521d\u4e2d\u6570\u5b66\u5408\u96c6\u767e\u5ea6\u7f51\u76d8\u4e0b\u8f7d
\u94fe\u63a5\uff1ahttps://pan.baidu.com/s/1znmI8mJTas01m1m03zCRfQ
?pwd=1234 \u63d0\u53d6\u7801\uff1a1234
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1.若甲商场花费＞乙商场花费
100+（x-100）90％＞50+（x-50）95％
解得x＜150 ∴当x＜150时甲商场花费＞乙商场花费
2.若甲商场花费＜乙商场花费
100+（x-100）90％＜50+（x-50）95％
解得x＞150 ∴当x＞150时甲商场花费＜乙商场花费
3.若甲商场花费＝乙商场花费
100+（x-100）90％=50+（x-50）95％
解得x=150 ∴当x＝150时甲商场花费＝乙商场花费
绛旓細鍒嗘瀽锛氾紙1锛夊厛璁捐繍寰B涓ゅ湴鐨勮揣鐗╀负x鍚紝鏍规嵁杩愬線A鍦扮殑鏁伴噺姣旇繍寰B鍦板20鍚ㄥ拰鐢层佷箼銆佷笝涓変釜浠撳簱鍒嗗埆瀛樻湁璐х墿120鍚ㄣ100鍚ㄣ80鍚紝鍒楀嚭浠ｆ暟寮锛屾眰鍑簒鐨勫硷紝鍗冲彲寰楀嚭绛旀锛涳紙2锛夋牴鎹鎰忓緱鍒颁竴鍏冧竴娆′笉绛夊紡缁勶紝鍐嶆壘绗﹀悎鏉′欢鐨勬暣鏁板煎嵆鍙紟锛3锛夋眰鍑烘昏垂鐢ㄧ殑鍑芥暟琛ㄨ揪寮忥紝鍒╃敤鍑芥暟鎬ц川鍙眰鍑烘渶灏...
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绛旓細瑙ｏ細涓5x+4涓=8-2 涓5x+4涓=6 鈭5x+4=6鎴5x+4= -6 5x=2 5x= -10 x=2梅5 x= -10梅5 x=0.4 x= -2
绛旓細锛2锛夋牴鎹紙1锛変腑姹傚嚭鐨勭偣M鐨勫潗鏍囧緱鍒癕C涓嶮D鐨勯暱锛屼粠鑰屾眰鍑篛A涓嶰B鐨勯暱锛屽緱鍒扮偣A涓庣偣B鐨勫潗鏍囷紝璁惧嚭涓娆″嚱鏁扮殑瑙ｆ瀽寮忥紝鎶婄偣A涓庣偣B鐨勫潗鏍囧垎鍒唬鍏ヨВ鏋愬紡涓眰鍑簁涓巄鐨勫硷紝纭畾鍑虹洿绾緼B鐨勮〃杈惧紡锛瑙ｇ瓟锛氳В锛氾紙1锛夎繃鐐筂浣淢C鈯杞达紝MD鈯杞达紝鈭礎M=BM锛屸埓鐐筂涓篈B鐨勪腑鐐癸紝鈭礛C鈯杞达紝MD鈯杞...
绛旓細锛堟湭鐭ユ暟鏈楂樻鏁颁负1锛3-m 鈮 0 m 鈮 -3 锛3-m绛変簬0鐨勮瘽鏈煡鏁板氨涓嶅瓨鍦ㄤ簡锛夆埓m=3 10銆 x+2=3 7x=6x-7 瑙ｏ細x+2-2=3-2 瑙ｏ細7x+7-6x =6x-7-6x-7 x =1 x+7 =0 x = -7 -3/2x=5/2+x -2/3x= -1/2 瑙ｏ細-3/2x脳2=...
绛旓細鈶3鈭2锛 (绛夎叞鐩磋涓夎褰笁杈圭殑姣旀槸1锛1锛氣垰2)鈶风敱宸茬煡鏉′欢锛歛=2+b 鈭碘垹C=90掳 鈭(2+b)²锛媌²=10² 锛岃В寰楋細b=6鎴朾=-8(鑸)鈶哥敱宸茬煡鏉′欢璁撅細a=n-1 锛宐=n锛宑=n+1 鈭礱²锛媌²=c²鈭(n-1)²锛媙²=(n+1)²n&#...
绛旓細锛1锛夎绉熺敤鐢茬璐ц溅 x 杈嗭紝鍒欑鐢ㄤ箼绉嶈揣杞 8-x 杈嗐傚彲鍒椾笉绛夊紡缁勶細4x+2(8-x) 鈮 20 锛寈+2(8-x) 鈮 12 锛岃В寰楋細2 鈮 x 鈮 4 锛屽垯鏈 3 绉嶆柟妗堬細鈶 绉熺敤鐢茬璐ц溅 x = 2 杈嗭紝绉熺敤涔欑璐ц溅 8-x = 6 杈嗭紱鈶 绉熺敤鐢茬璐ц溅 x = 3 杈嗭紝绉熺敤涔欑璐ц溅 8-x = 5 杈嗭紱鈶 ...
绛旓細鍒檏=8锛屼唬鍏ュ師鏂圭▼寰楋細x²-16k+64=0锛(x-8)²=0 x=8 鈭村懆闀=5+8+8=21 鈶″綋鑵伴暱涓5鏃讹紝鍗充袱鏍逛腑鏈変竴鏍逛负5 浠ｅ叆鏂圭▼寰楋細5²-5(8+k)+8k=0锛岃В寰梜=5 鍒欏師鏂圭▼涓猴細x²-13x+40=0锛(x-5)(x-8)=0 x=5鎴8 鈭村懆闀=5+5+8=18 缁间笂鎵杩帮紝杩欎釜绛夎叞...
绛旓細瑙ｏ細锛1锛変箼锛涚敳锛涗箼妲戒腑閾佸潡鐨勯珮搴︿负14cm锛涳紙2锛夎绾挎AB銆丏E鐨勮В鏋愬紡鍒嗗埆涓猴細y1=k1x+b1锛寉2=k2x+b2锛屸埖AB缁忚繃鐐癸紙0锛2锛夊拰锛4锛14锛夛紝DE缁忚繃锛0锛12锛夊拰锛6锛0锛夆埓 b1锛2 4k1+b1锛14 锛岃В寰 k1锛3 b1锛2 锛宐2锛12 6k2+b2锛0 锛岃В寰楋細k2锛−2 b2锛12 锛屸埓瑙ｆ瀽寮...
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