Question

If the sum of three numbers is 10 and the sum of their squares is 38, find the sum of the products of the three numbers taking two at a time.​

Answer 1

QUESTION :

If the sum of three numbers is 10 and the sum of their squares is 38, find the sum of the products of the three numbers taking two at a time.

Step-by-step explanation:

given

a+b+c=10

a^2+b^2+c^2=38

ab+bc+ac=?

consider (a+b+c)^2=a^2+b^2+c^2+2(ab+bc+ac)

100=38+2(ab+bc+ac)

100-38=2(ab+bc+ac)

62/2=ab+bc+ac

31=ab+bc+ac

Answer 2

Answer:

the anser of this question is 31

Step-by-step explanation:

x+y+z=10

x²+y²+z²=38

(x+y+z)²=x²+y²+z²+2(xy+yz+zx)

(10)²= 38+2(xy+yz+zx)

100=38+2(xy+yz+zx)

100-38=2(xy+yz+zx)

62/2=xy+yz+zx

31=xy+yz+zx

so the answer is 31