Question

If a and b are the zeroes of the polynomial x2-11x +30, Find the value of a3 + b3.

Answer 1

x²-11x+30

x²-6x-5x+30 = 0

x(x-6)-5(x-6) = 0

(x-6)(x-5) = 0

x-6 = 0 | x-5 = 0

x = 6 | x =5

Therefore,5 and 6 are zeroes of the given polynomial.

a = 5 and b = 6

a³+b³ = 5³+6³

= 125+216

= 341

Hope it helps

Answer 2

To obtain zeroes of the polynomial x²-11x+30 , we will First factorize it →

x² - 11x + 30

or, x² - 6x - 5x + 30

or, x(x-6) - 5(x-6)

or, (x-5) (x-6)

Therefore ,

x-6 = 0
or, x = 6

x-5 = 0
or, x = 5

Zeroes of polynomial are 5 and 6

So let a=5 and b=6

Value of a³+b³→

5³+6³

= 125 + 216

= 341
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