Question

Create a matrix. use a graphing calculator to solve the system using the rref function.

-11x-4y=36
5x+5y=-10

Answer 1

`x=-(44)/(7)`

`y=(58)/(7)`

Explanation:

Arrange the equations so that all the variables are in columns (x as the first column, y as the second, equals a number as the third):

-11x - 4y = 36

5x + 5y = -10

Define and edit Matrix A. We need a 3 x 2 matrix. Input the coefficients and constant:

`\left[\begin{array}{ccc}-11&-4&36\\5&5&-10\end{array}\right]`

Find rref function, enter matrix A: rref([A]) (press enter)

This gives you:

`\left[\begin{array}{ccc}1&0&-(44)/(7)\\0&1&(58)/(7)\end{array}\right]`

which means:

`x=-(44)/(7)`

`y=(58)/(7)`