Question

The sum of 2 numbers is 7, the sum of their cubes is 133. Find the sum of their squares

Answer 1

Answer:

29

Step-by-step explanation:

Let two number be a and b,

According to question,we get,

a+b=7

a

3

+b

3

=133

Now,

(a+b)

3

=a

3

+b

3

+3ab(a+b)

=>7

3

=133+3ab(7)

=>

21

343−133

=ab

=>ab=

21

210

=>ab=10

Now,

(a+b)

2

=a

2

+b

2

+2ab

=>7

2

=a

2

+b

2

+2(10)

=>a

2

+b

2

=49−20

=>a

2

+b

2

=29