Question

If a+b+c=9and ab+bc+ac=26,find a^2+b^2+c^2

Answer 1

Answer:

29

Step-by-step explanation:

$(a + b + c) {}^{2} = a {}^{2} + b {}^{2} + c {}^{2} + 2(ab + bc + ca) \\ 9 {}^{2} = a {}^{2} + b { }^{2} + c {}^{2} + 2 \times 26 \\ 81 = a {}^{2} + b {}^{2} + c {}^{2} + 5 2\\ a {}^{2} + b {}^{2} + c {}^{2} = 29$