Question

if a=6+b and ab = 15 then find the value of a²+b² and a³-b³​

Answer 1

Answer: a³- b³ = 486 and a² + b² = 66

Step-by-step explanation: Here we know that  a=6+b so we can say that      

a - b = 6   and   ab = 15, and now we have to find a²+b² and a³-b³

a - b = 6 ​

a³-b³​ =  (a-b)(a² + ab + b²)

Here we have the values of a-b (which equals  6) and we also know that

ab =15 , so lets find a² + b²

a - b = 6

(Now lets square both sides)

(a-b)² = 6²

a² -2ab + b² = 36

Now we know that (ab =  15)( So 2ab = 30)

a² - 30 + b² = 36

a² + b² = 36 + 30

a² + b² = 66

Now we know that a² + b² = 66 so we can find the value of a³-b³​ now.

a³-b³​ =  (a-b)(a² + ab + b²)

Now we know that  a - b = 6

and a² + b² = 66 and ab = 15

So now we will substitute the values

a³-b³=(6)(a² + b² + ab)

a³-b³=(6)(66 +15)

a³-b³ = (6)(81)

a³-b³ = 486

Therefore a³- b³ = 486 and a² + b² = 66

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Answer 2

Answer:

ஆன்சர் அஸ் ஆக்சன் இட் இஸ் ஈக்குவல் டு டோ இஸ்யூ 3