Question

If sum of two number is 13 and product of the number is 42.find the sum of the squares of the number

Answer 1

Let the two numbers be a and b
According to given
a+b=13 , ab=42
a^2+b^2=?
a^2+b^2=(a+b)^2-2ab [since (a+b)^2=a^2+b^2+2ab ]
=13^2-2 (42)
=169-84
=85

Answer 2

Let the two numbers be 'a' and 'b'
a + b = 13
a × b = 42
Since 6 × 7 = 42
And 6 + 7 = 13
a = 6 and b = 7
Then, a square + b square = ?
Therefore, a × a + b × b
= 36 + 49
= 85

Therefore, answer = 85...
Hope it helps...