1.4(x+2)^2-9(x-3)^2=02.(mx-n)^2-b^2=0(m≠0)3.(x-m)^2=n(x^2-m^2)(n≠1)4.x^2-1=1/2x5.x(x-3)+2=06.x^2+y^2-2x+4y+5=0 则x+y=
热心网友
昨天问了啊1。4(x+2)^2-9(x-3)^2=0化为:(2x+4)^2-(3x-9)^2=0即(2x+4+3x-9)(2x+4-3x+9)=0整理理(5x-5)(-x+13)=0解得x=1或x=13---------------2。(mx-n)^2-b^2=0(m≠0)化为(mx-n-b)(mx-n+b)=0解得x=(n+b)/m或x=(n+b)/m---------------3。(x-m)^2=n(x^2-m^2)(n≠1)即(x-m)^2-n(x^2-m^2)=(x-m)[(x-m)-n(x+m)]=(x-m)[x(1-n)-(m+nm)]=0解得x=m或x=(m+nm)/(1-n)---------------4。x^2-1=1/2x自己用求根公式解一下---------------5。x(x-3)+2=0化为(x-1)(x-2)=0解得x=1或x=2---------------6。x^2+y^2-2x+4y+5=0 则x+y= ∵x^2+y^2-2x+4y+5=(x-1)^2+(y+2)^2=0∴x=1;y=-2∴x+y=1-2=-1。
热心网友
1。4(x+2)^2-9(x-3)^2=0 (2(x+2)+3(x-3))*(2(x+2)-3(x-3))=0(5x-5)*(13-x)=05x-5=0 or 13-x=0x=1 or x=132。(mx-n)^2-b^2=0(m≠0)((mx-n)+b)*((mx-n)-b)=0(mx-n)+b=0 or (mx-n)-b=0 x=(n-b)/m or x=(n+b)/m3。(x-m)^2=n(x^2-m^2)(n≠1) (x-m)^2=n(x-m)(x+m) (x-m)^2-n(x-m)(x+m)=0 (x-m)*(x-m-nx-nm)=0 x-m=0 or x-m-nx-nm=0 x=m or x=(n+nm)/(1-n)4。x^2-1=1/2xx^2-1-1/2x=0(x-1)*(x+1/2)=0x=1 or x=-1/25。x(x-3)+2=0 x^2-3x+2=0(x-1)*(x-2)=0x=1 or x=26。x^2+y^2-2x+4y+5=0 x^2-2x+1+y^2+4y+4=0 (x-1)^2+(y+2)^2=0 x-1=0 y+2=0 x+y=-1。