Question

Rumus dari x1 kuadrat + x2 kuadrat + x3 kuadrat

Answer 1

Answer 2

.
x1² + x2²+x3³ = (x1+x2+x3)² - 2(x1.x2+x1.x3+x2.x3)
JIka dalam bentuk ax³+bx²+cx+d = 0 ,akar-0akarnya x1.x2 dan x3
berlakulah rumus :
(x1+x2+x3) = -b/a
x1.x2+x1.x3+x2.x3 = c/a
sehingga  
x1² + x2²+x3³ = (x1+x2+x3)² - 2(x1.x2+x1.x3+x2.x3)
x1² + x2²+x3³ =(-b/a)² - 2(c/a) = (b²-2ac)/(a)