Question

(iv) If a = 10 and c = 21, then find b. (v) If a=9 and b = 9, then find c.
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Answer 1

Step-by-step explanation:

Given a+b+c=9 & ab+bc+ca=26

As a

3

+b

3

+c

3

−3abc=(a+b+c)(a

2

+b

2

+c

2

−ab−bc−ca)

⇒(a

3

+b

3

+c

3

−abc)=(a+b+c)[(a+b+c)

2

−3(ab+bc+ca)]

⇒(a

3

+b

3

+c

3

−3abc)=9[81−78]=27

Answer 2

Answer:

ans 27

Step-by-step explanation:

Given a+b+c=9 & ab+bc+ca=26

As a3+b3+c3−3abc=(a+b+c)(a2+b2+c2−ab−bc−ca)

⇒(a3+b3+c3−abc)=(a+b+c)[(a+b+c)2−3(ab+bc+ca)]

⇒(a3+b3+c3−3abc)=9[81−78]= 27