-3x + 4y = 20
6x + 3y = 15

x = 0

y = 5

Step-by-step explanation:

-3x + 4y = 20  (i)

6x + 3y = 15  (ii)

(i) * 2     - 6x + 8y = 40

(ii)           6x + 3y = 15           (Now add, x will be eliminated}

                     11y =  55

y = 55/11

y = 5

Plug in y =5 in equation (i)

-3x + 4*5 = 20

-3x + 20 = 20

-3x = 20 - 20

-3x = 0

x = 0  

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