Variation for y and t

[nycmathguy]

Section 1.10
Question 79

Let y = 2x + 2 and t = x + 1.
What kind of variation do y and t have? Explain.

Let me see.

If I factor 2x + 2, y becomes 2(x + 1).
I know that (x + 1) = t.

So, I then can say y = 2t.
I know that 2t means 2 times t.

I am going to take a wild guess here.
The variation that y and t have is joint variation.

You say?

 

[MathLover1]

if y = 2t, then y = kt The variation that y and t have is ?????????????

 

[nycmathguy]

if y = 2t, then y = kt The variation that y and t have is ?????????????

Direct variation.