a^2+b^2+c^2=121 and the question is: what is a+b+c=?
The answe is 17 but I don´t know how to prove it and which sort of method I should use. It should be quite easy since the course as a whole is considered to be basic
since a + b + c = 17, then one way could be: a=2, b=6, c=9. So, you have:
a^2 + b^2 + c^2 = 2^2 + 6^2 + 9^2 =4 + 36 + 81 =121.