Question

if a + b equal to 9 ab equal to 20 find the value of a cube plus b cube

Answer 1

your ans

given:-

a+b=9

Ab=20

to find:-

a3+b3

use formula:-

(a+b)3=a3+b3+3ab(a+b)

(9)3=a3+b3+3×20(9)

729=a3+b3+540

189=a3+b3

Answer 2

$<b > Ello!!$

Here's your answer

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Given ,

• ( a + b ) = 9

• ab = 20

To find the value of , a³ + b³

Now ,

a³ + b³

= ( a + b )³ - 3ab ( a + b ) [ • Using Identity ]

= ( 9 )³ - 3 × 20 × 9 [ • Putting the values ]

= 81 - 540

= - 459 [ ★ Required answer ]

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Hope it helps!!