Question

I'm confused on how to go about solving this, I got to this part:

2x+y+32=20
-3y-3z=2
-3y-13z=-6
but I'm not even sure if I did that correctly or where to go next

Answer 1

• (3, -4, 6)

Explanation:

The last equation has 2 variables

If we double the first equation and subtract the second one from it, we get rid of y and then comparing the new equation with the last one we can easily solve it

Step 1

• 2(2x + y + 3z) = 2*20
• 4x + 2y + 6z = 40

Step 2

• 4x - x + 2y - 2y + 6z - (-z) = 40 - (-11)
• 3x + 7z = 51

Step 3

• 3x + 7z - (3x - 2z) = 51 - (-3)
• 7z + 2z = 54
• 9z = 54
• z = 6

Then finding x

• 3x - 2*6 = -3
• 3x = 12 - 3
• 3x = 9
• x = 3

Then finding y using the first equation

• 2*3 + y + 3*6 = 20
• y + 24 = 20
• y = -4

The answer:

• (3, -4, 6)