The graph of f(t)=6•2^t shows the value of a rare coin in year t. what is the meaning of the y-intercept?

Notice that the y-intercept is the point on the graph where x=0 and y equals some value (determined by the equation where x = 0).

In this equation, the y-intercept would be where t = 0. Since t represents a year, the y-intercept represents the value of the coin in year 0, or when it was purchased. The value of the coin in this year 0 is determined by inserting 0 into our equation for t. Doing this, we find that the value of the coin in year 0 is 6. This fact correlates to answer D, "When it was purchased (year 0), the coin was worth $6"

check the picture below.

dilation scale factor 2: starting with δabc, draw the dilation image of the triangle with a center at the origin and a scale factor of two. notice that every coordinate of the original triangle has been multiplied by the scale factor (x2). dilation with scale factor 2, multiply by 2.