Question

Paige is comparing costs for renting a steam cleaner from two different stores. Each store charges a set rental fee plus an hourly rate for each hour the steam cleaner is rented.



The costs for each store are represented in this system of equations where x is the hours rented and y is the total cost for renting the machine.



{
15
x
+
45
=
y
20
x
+
35
=
y



Which matrix equation is equivalent to the system of equations above?

Answer 1

First rewrite each equation with all terms on the left:
15x - y = -45
20x - y = -35

As a matrix equation this is
[ [15, -1],
[20, -1] ] [ x
y ] = [ -45
-35 ].