I'm trying to help my daughter with her homework. I'm not looking for an answer, but the process.
She has been asked to solve this:
[ [ ?, 36, ? ] [ 9, 6, 4 ] [ -12, ?, ? ] ]
My approach was to substitute letters for the missing values:
[ [ A, 36, B ] [ 9, 6, 4 ] [ -12, C, D ] ]
Then I could solve for the unknowns:
9 + 6 + 4 = 19 A + 36 + B = 19 -12 + C + D = 19 ...
Solving the equations resulted in most of the rows, columns and diagonals adding up to 19 - however, not all did. I ended up with:
A = -42 B = 25 C = -24 D = 55
I'm not clear where I'm going wrong.
My Math knowledge is very poor, simple clear answers will be preferred over complex answers.