Question

If a+b+c=4,and a square +b square +c square =14,find ab+bc+ca.

Answer 1

(a+b+c)^2 = a square +b square+c square +2(ab+BC+ac) then put the values of each then our final answer is 1

Answer 2

(A+B+C)²=A²+B²+C² +2(AB+BC+CA)
16=14+2(AB+BC+CA)
16-14=2(AB+BC+CA)
2/2=AB+BC+CA
AB+BC+CA=1