Brainliest for correct answer please help

A. x = 12

Step-by-step explanation:

Interior angle + interior angle = exterior angle

9x + 7 + 3x + 4 = 155

12x + 11 = 155

      -11       -11

12x = 144

12       12

x = 12

solution:

→c= a b , that is product of a and b is possible only when when a is m × n matrix and b is n × p matrix.

that is, number of columns of a= number of rows of b.

so, size of matrix , c= a b is , if a = (m × n)matrix

b= (n × p)matrix

then a b = [ (m × n)matrix] ×[   (n × p)matrix ]

→→c= a b= [m × p ] matrix

→→size of product a b will be equal to = number of rows of a × number of columns of b