Question

use the matrix tool to solve the system of equations enter the answer as an ordered pair. 8x+5y=9 -x+y=7

Answer 1

x = -44/13

y = -65/13

Explanation:

Using matrix form means using the crammers rule

The matrix form of the expression is written as;

`\left[\begin{array}{ccc}8&5\\-1&1\\\end{array}\right] \left[\begin{array}{ccc}x\\y\\\end{array}\right] = \left[\begin{array}{ccc}9\\7\\\end{array}\right]`

AX = B

taking the determinant of A;

|A| = 8(1) - 5(-1)

|A| = 8 + 5

|A| = 13

After replacing the first row with the column matrix;

`A_x =\left[\begin{array}{ccc}9&5\\7&-1\\\end{array}\right]`

|Ax| = 9(-1)-5(7)

||Ax| = -9 - 35

|Ax| = -44

x = |Ax|/|A|

x = -44/13

similarly for y

`A_x =\left[\begin{array}{ccc}8&9\\-1&7\\\end{array}\right]`

|Ay| = 8(7)+9

|Ay| = 56+9

|Ay| = 65

y = |Ay|/|A|

y = -65/13