PLEASE HELP! I don't get it

Option 'C i.e. Subtract to eliminate y' is the correct option.

Step-by-step explanation:

Given the system of equations

-6x + 7y = -54

-7x + 7y = -56

The first step we need to do is to subtract to eliminate y, because 7y and -7y will cancel each other.

x + 0y = 2

x = 2

Therefore, we get x = 2 after we implemented the fist step to subtract to eliminate y.

Hence, option 'C i.e. Subtract to eliminate y' is the correct option.

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