Question

If a = 1 , b = -2, c = 3 then find the value of a² + b² + c²+ ab + bc + ca

please give answer with full explanation​

Answer 1

Given: a = 1, b = -2, c = 3  

To find = $a^ 2+b^{2}+c^{2}+ab+bc+ca$ = ?

Solution:  We put the given values of the following variables into their respective places in the given equation

$(1)^{2} + (-2)^{2} + (3)^{2} + (1)(-2) + (-2)(3) +(3)(1)$

therefore: 1 + 4 + 9 + (-2) +(-6) + 3 = 0

                 1 + 4 + 9 -2 -6 + 3 = 0

                  17 - 8 = 0

                  = 9

Therefore the solution of the given equation is 9.