Will Mark Brainlest Help Please !!!!!

Answer:
a = - 2, b = 3
Step-by-step explanation:
B + C
= [tex]\left[\begin{array}{ccc}6&4\\2&6\\\end{array}\right][/tex] + [tex]\left[\begin{array}{ccc}1&-1\\2a&-6\\\end{array}\right][/tex] ( add corresponding elements )
= [tex]\left[\begin{array}{ccc}7&3\\2+2a&0\\\end{array}\right][/tex]
Then
[tex]\left[\begin{array}{ccc}5&b\\a&0\\\end{array}\right][/tex] = [tex]\left[\begin{array}{ccc}7&3\\2+2a&0\\\end{array}\right][/tex]
Equating corresponding elements gives
b = 3
a = 2 + 2a ( subtract 2a from both sides )
- a = 2 ( multiply both sides by - 1 )
a = - 2