Solve the system.

Question

x+4y-6z=-1

2x-y+2z=-7

-x+2y-4z=5

Answer 1

If we add the first and the third equation, we get 6y - 10z = 4

To get y, z; we will multiply the last equation by 2, so that we get a -2x and when added to the 2nd equation, it yields only y, z

2x - y + 2z = -7

-2x + 4y - 8z = 10 (expanded by 2 )

+

____________

3y - 6z = 3 (simplify by 3 )

y - 2z = 1

These two bolded equations will give y, & z.

1st one, simplified by 2,

3y - 5z = 2

-3/y - 2z = 1

3y - 3y -5z + 6z = 2 - 3

z = -1

y = -1

Then plug y nd z and find x ( 2x - (-1) + 2(-1) = -7

2x + 1 -2 = -7

2x = -6, x = -3