Question

X+y=7, xy=0 then find x3+y3

Answer 1

Answer:

343

Step-by-step explanation:

xy = 0

x = 0

y = 7

343

is the answer

Answer 2

Correct Question :

If (x + y) = 7 and, xy = 0. Then Find (x³ + y³)

AnswEr :

• We know the Formula ;

⇒ (x + y)³ = x³ + y³ + 3xy(x + y)

• Plugging the Values

⇒ ( 7 )³ = x³ + y³ + 3 × 0 × ( 7 )

⇒ ( 7 × 7 × 7 ) = x³ + y³ + 0

⇒ x³ + y³ = 343

჻ Required Value is 343.

• Verification :

» (x + y)³ = x³ + y³ + 3xy(x + y)

» ( 7 )³ = 343 + 3 × 0 × ( 7 )

» ( 7 × 7 × 7 ) = 343 + 0

» 343 = 343 Hence, Verified

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• Some Important Formulas ;

⋆ (a + b)² = a² + b² + 2ab

⋆ (a – b)² = a² + b² – 2ab

⋆ (a + b)³ = a³ + b³ + 3ab(a + b)

⋆ (a – b)³ = a³ – b³ – 3ab(a – b)

⋆ (a ± b)⁴ = a⁴ ± 4a³b + 6a²b² ± 4ab³ + b⁴