Final answer:
To eliminate the y-term from the third equation, you can use the method of elimination. Multiply the second equation by -3 and add it to the third equation, then solve for z.
Step-by-step explanation:
Step 1:
Multiply the second equation by -3 to make the coefficient of y the same as the coefficient of y in the third equation. The new equation is -3y + 9z = -30.
Step 2:
Add the second and the new equation to eliminate y. The result is -3y + 9z + (y - 3z) = -20. Simplify to get 6z = -20.
Step 3:
Solve for z by dividing both sides of the equation by 6. The final answer is z = -20/6 or -10/3.