Question

if alfa and beta are the roots
of the quadratic x2+5x-1=0 then find alfa3+ beta3​

Answer 1

Answer:

-140

Step-by-step explanation:

From the given equation,

α+β=-5  

αβ=-1

α³+β³=(α+β)(α²+β²-αβ)

        =(α+β)[(α²+β²+2αβ)-3αβ]

        =(α+β)[(α+β)²-3αβ]

        =(-5)[(-5)²-3(-1)]

        =-5 × (25+3)

        =-5 × 28

        =-140