Question

if a2+b2+c2=30 and a+b+c=10 then find the value of ab+ bc+ ca​

Answer 1

Step-by-step explanation:

(a+b+c) 2= a2+b2+c2+2ab+2bc+2ca

10 x10=30+2(ab+bc+ca)

100-30 =2(ab+bc+ca)

35=ab+bc+ca

Answer 2

Answer:

35

Step-by-step explanation:

(a+b+c)²=a²+b²+c²+2ab+2bc+2ca

=>10²=30+2ab+2bc+2ca

=>100-30=2(ab+bc+ca)

=>70=2(ab+bc+ca)

=>ab+bc+ca=70/2

∴ab+bc+ca=35