Question

Name the point that corresponds to (4, 10) after applying the specified transformations to the graph of y=5/2 x(hint: if you are not sure, draw a sketch) a reflection across the x-axis followed by a vertical stretch by a factor of 2 a. (4, 23) c. (-4, 7) b. (4, -20) d. (12, 15)

Answer 1

Solution

We are first given

$\begin{gathered} y=\frac{5}{2}x \\ \text{and the point} \\ (4,10) \end{gathered}$

A reflection across the x-axis

$y=-\frac{5}{2}x$

A vertical stretch by a factor of 2

$y=2(-\frac{5}{2}x)$

Now, put x = 4

$y=2(-\frac{5}{2}x)=2(-\frac{5}{2}(4))=-20$

We have the point

$(4,-20)$

The graph below will help

Therefore, the answer is

$(4,-20)$