Question

if a and B are the roots of x²+5x-1=0 then find the value of a³+ B³​

Answer 1

Step-by-step explanation:

sum of roots of ax^2+bx+c is-b/a, product of roots = c/a

a+b = -5/1=-5

ab = -1/1=-1

(a+b)³ = a³+ b³ + 3ab(a+b)

(-5)³ = a³+b³ +3×(-1)×(-5)

-125 = a³+b³ +15

a³+b³ = -125-15 = -140