Q:  Use the equation y = 3x + 1.  Find y for x = 1, 2, 3, and 4.

A:  This is really four questions in one!  We have to:

(a) Find y when x=1

(b) Find y when x=2

(c) Find y when x=3

(d) Find y when x=4

For part (a), plug x=1 into the equation:

y = 3x + 1

y = 3(1) + 1

y = 3 + 1

y = 4

Similarly, for part (b) plug x=2 into the equation:

y = 3x + 1

y = 3(2) + 1

y = 6 + 1

y = 7

Same for parts (c) and (d):

(c): When x=3 we have:

y = 3x + 1

y = 3(3) + 1

y = 9 + 1

y = 10

(d) When x=4, we have:

y = 3x + 1

y = 3(4) + 1

y = 12 + 1

y = 13