Question

I forgot how to solve for two variables... Please check if I solved both problems properly! Thank you.

Equations: (solve for t and z)
12t + 4z = 80
2t + 4z = 20

My answer: t = 2, z = 14

The steps:
(simplified it)
z = 20 - 3t, z = 5 - 0.5t
(equated both sides to isolate for t)
20 - 3t = 5 - 0.5t
t = 2
(sub t = 2 into one of the equations)
z = 20 - 3(2)
z = 14

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Equations: (solve for t and z)
z = 2 + 6t
z 20 - 3t

My answer: t = 2, z = 14
(I did the same steps like the previous question, my answer is kind of iffy because it's the same???)

Answer 1

Your answers are wrong.
20-3t=5-.5t does NOT come out t=2

redo that. Another quick way to do this is take your original equations, subtract the second from the first, and you get
10t=60 which is pretty fast to solve in your head.