学霸们,帮忙解解方程组
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a*a-b*b=-8<0
a*a<b*b
|a|<|b|
2*a*b=6>0
a、b同号,
把b=3/a代入第一个方程得:
a^4+8*a*a-9=0
(a*a+9)*(a*a-1)=0
a*a=1
a=1,b=3
或
a=-1,b=-3
ab=3,a=3/b
(3/b)^2-b^2=-8
同时乘以b^2得b^4-8b^2-9=0
因式分解得:(b^2-9)(b^2+1)=0
b^2=9,b=±3,a=±1
绛旓細鍥炵瓟锛歛*a-b*b=-8<0 a*a<b*b |a|<|b| 2*a*b=6>0 a銆乥鍚屽彿, 鎶奲=3/a浠e叆绗竴涓鏂圭▼寰: a^4+8*a*a-9=0 (a*a+9)*(a*a-1)=0 a*a=1 a=1,b=3 鎴 a=-1,b=-3
绛旓細绗2涓鏂圭▼涓棿搴旇鏄噺鍙锋墠瀵癸紒
绛旓細鍥炵瓟锛歺=3.y=4
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绛旓細鍥炵瓟锛氱敱涓嶇瓑寮3x+1>5(x-1)寰:x<3 鐢变笉绛夊紡4/3 x-6鈮6-5x/3寰:x鈮8/3 鈭翠笉绛夊紡缁勭殑瑙i泦鏄:8/3鈮 <3
绛旓細鍥炵瓟锛歺=0.5,y=涓1銆
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绛旓細璁句粠鐢插埌涔 涓婂潯涓簒鍗冪背 骞宠矾涓簓鍗冪背 x/3+y/4+(17-x-y)/5=4.6 (1) (17-x-y)/3+y/4+x/5=4.2(2)鐢憋紙1锛夊緱 20x+15y+204-12x-12y=276 8x+3y=68(3) 鐢憋紙2锛夊緱 340-20x-20y+15y+12x=252 8x+5y=88(4)(4)-(3) 2y=20 y=10 浠e叆锛4锛...
绛旓細w x y z w + x = 8 w + y = 13 y - z = 6 x + z = 8
绛旓細鈶+鈶: 5x-2z=14 鈶 鈶-鈶: 5x-z=-10 鈶 鈶-鈶: -z=24, 寰楋細z=-24 浠e叆鈶わ細 x=(z-10)/5=14/5 浠e叆鈶狅細 y=3x+2z-3=42/5-48-3=-213/5