Question

What is the solution of the system? Solve using matrices.

{ x+2y=9
{x+y=1

Answer 1

Explanation:

// Solve equation [2] for the variable x

[2] x = y + 1

// Plug this in for variable x in equation [1]

[1] (y +1) - 2y = 9

[1] - y = 8

// Solve equation [1] for the variable y

[1] y = - 8

// By now we know this much :

x = y+1

y = -8

// Use the y value to solve for x

x = (-8)+1 = -7

Solution :

{x,y} = {-7,-8}