Question

f(x) = 3x - 7
g(x) = 3x + 8

The graph of g(x) is obtained by shifting up the graph of f(x) by _____ units

Answer 1

Have you drawn the graphs?

Answer 2

not yet @alekos

Answer 3

could you help me create a graph @alekos

Answer 4

You "shift up" by increasing y-coordinates.

For every y on f(x), you have: y = 3x - 7
For every y on g(x), you have y = 3x + 8

What is the difference between the 2? How much "above" f(x) does g(x) lie in the plane?

(You could also draw the graphs, but it shouldn't be necessary to answer the problem. Just look at the equations.... especially the y-intercepts.)

Answer 5

Since these are both lines with the same slope, the vertical difference between the y-intercepts is the vertical difference between the two lines, at every value of x.

Answer 6

thanks so much that really helped! @DebbieG