Question

Solve the system of inequality:
x + y + z = -­1
2x + 4y + z = 1
x + 2y -­ 3z = ­-3

Answer 1

elimination method?

Answer 2

@rebeccaxhawaii Yes!

Answer 3

I think you can type them in as a matrix in the graphing calculator and then hit rref.

Answer 4

@anthonyym unfortunately I don't own a graphing calculator :/

Answer 5

Use the first 2 equations to get x and z in terms of y. Then substitute those values in 3rd equation to solve for y. Once you have y, get values of x and z from original substitutions. This is probably fairly hard to follow, but here is the actual equation solving, i just did.

z = -1 -x -y ---> z = 1 - (2-3y) -y = 1 - 2 + 3y - y = -1 + 2y
z = 1+2(8/3) = 19/3

2x + 4y + (-1-x-y) = 1
2x + 4y -1 -x -y = 1
x + 3y -1 = 1
x + 3y = 2
x = 2 -3y = 2 - 3(8/3) = -6

x + 2y -­ 3z = ­-3
2-3y +2y - 3 (-1+2y) = -3
2 -y + 3 - 2y = -3
5 - 3y = -3
y = 8/3

Answer 6

Thank god, that was really helpful thank you so much!