7. Andy's Rental Car service charges an initial fee of $20 plus an additional fee of $50 per day to rent a car Buddy's Rental Car charges an initial fee of $60 plus an
additional fee of $30 per day Write and solve an equation to determine the number
of days for the cost of the two companies to be the same,
A. 20x + 50 = 60x + 30
B. 80 - 80x
C. 20 + 50x = 60 + 30x
D. 70x90

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

answer:

it is general formula that is used to write value to its excet position

a11 a12 a13

a21 a22 a23

it is the example of order 2 by 3 matrix in this

a11 means value occur in 1 st row 1st column

a12 means value occurs in 1st row 2nd column

a13 means value occur in 1st row and 3rd column

a21 means value occurs in 2nd row and 1st column

a22 means value occurs in 2nd row and in 2nd column

a23 means value occurs in 2nd row and in 3rd column