To find the letters

For this case we must subtract the given matrices and find the values of a, b, c and d:
Subtracting term from term we have:[tex]a = 5-4 = 1\\b = 2-1 = 1[/tex]
We have that different signs are subtracted and the sign of the major is placed.
[tex]c = 3-6 = -3\\d = 0-7 = -7[/tex]
Answer:
[tex]a = 1\\b = 1\\c = -3\\d = -7[/tex]