For the graph shown, each box has a width and height of 1.
The graph of f(2x) would be identical to the graph of f(x) if you change the scale on the x-axis, so that the width of each box would be ½ (but keep the height the same as it was).
a) On the original graph, there is the point (-4, 4). On the graph of f(2x), the coordinates of the point are (-2,4), so a = -2.
On the original graph, there is the point (4, -4). On the graph of f(2x), the coordinates of the point are (2, -4), so b = 2.
b) See the note above part a.
c) f(2x - 8) = f( 2(x - 4) ) This graph makes a horizontal shift of the graph of f(2x) 4 spaces to the right. The graph of f(2x - 8), which is f( 2(x - 4) ), is congruent to the graph of f(2x), just move it 4 spaces to the right.
Moving (-2,4) four spaces to the right creates (2,4), so c = 2.
Moving (2,-4) four spaces to the right creates (6, -4), so d = 6.
d) Draw the graph of f(2x), then move that graph 4 spaces to the right to create f(2x - 8).