Question

(a - b) = 3 and ab=5 then a3-b3=​

Answer 1

Answer:

12

Step-by-step explanation:

a-b=3

ab=5. (a=5/b)

a-b=3. (5/b-b=3

5=5b12

b=1)

a=5/b. a=5.

a(3)-b(3) =

Answer 2

a³-b³ = 72

GIVEN:- (a - b) = 3 and ab=5

TO FIND:- a³-b³

SOLUTION:-

As we know,

(a - b) = 3

By squaring both sides

(a - b)² = 3²

Applying the formula of (a - b)²

a² + b² - 2ab = 9

Putting the value of ab= 5

a² + b² - 2(5) = 9

a² + b² = 9 + 10

a² + b² = 19

As we know,

a³ - b³ = (a - b)(a²+ b²+ab)

Putting values of (a² + b²), (a - b) and ab=5

= 3(19+5)

= 3(24)

= 72

Hence, a³-b³ = 72

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