Question

a, b, c E R astfel încât V(a-v20)^2+ (b+V80) ^2+ (c-V180)^2 mai mic decat 0
Calculați a + b + c.​

E=apartine
V=radical

Answer 1

Răspuns:

V(a-V20) ^2= a-V20

(b+V80) ^2= b^2+80+2V80 (formula:a^2+b^2+2ab)

(c-V180)^2=c+180-2V180

(formula:a^2+b^2-2ab)

a-V20+b+80+2V80+c+180-2V180<0

<=>c+b+a-2V5+8V5-6V5+260<0

<=>a+b+c+260<0

<=>a+b+c<-260