a+b=8,ab-c²+8√2C=48,解方程bx²+cx-a=0
a=8-b
ab-c²+8√2C=48
(8-b)b-c²+8√2C=48
-b^2+8b-c²+8√2C=48
-(b-4)^2+16-(c-4√2)^2+32=48
(b-4)^2+(c-4√2)^2=0
b=4
c=4√2
a=4
原方程变成:
4x^2+4√2x-4=0
x^2+√2x-1=0
x=-√2/2±√6/2
a+b=8,ab-c²+8√2C=48,解方程bx²+cx-a=0
a=8-b
ab-c²+8√2C=48
(8-b)b-c²+8√2C=48
-b^2+8b-c²+8√2C=48
-(b-4)^2+16-(c-4√2)^2+32=48
(b-4)^2+(c-4√2)^2=0
b=4
c=4√2
a=4
原方程变成:
4x^2+4√2x-4=0
x^2+√2x-1=0
x=-√2/2±√6/2