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# A line segment has endpoints at (4 ,9 ) and (2 ,7 ). If the line segment is rotated about the origin by ( pi)/2 , translated vertically by -8 , and reflected about the x-axis, what will the line segment's new endpoints be?

Jun 26, 2018

#### Answer:

$\left(- 9 , 4\right) \text{ and } \left(- 7 , 6\right)$

#### Explanation:

$\text{since there are 3 transformations to be performed lsbel}$
$\text{the endpoints}$

$A = \left(4 , 9\right) \text{ and } B = \left(2 , 7\right)$

$\textcolor{b l u e}{\text{first transformation}}$

$\text{under a rotation about the origin of } \frac{\pi}{2}$

• " a point "(x,y)to(-y,x)

$A \left(4 , 9\right) \to A ' \left(- 9 , 4\right)$

$B \left(2 , 7\right) \to B ' \left(- 7 , 2\right)$

$\textcolor{b l u e}{\text{second transformation}}$

$\text{under a vertical translation } \left(\begin{matrix}0 \\ - 8\end{matrix}\right)$

• " a point "(x,y)to(x,y-8)

$A ' \left(- 9 , 4\right) \to A ' ' \left(- 9 , - 4\right)$

$B ' \left(- 7 , 2\right) \to B ' ' \left(- 7 , - 6\right)$

$\textcolor{b l u e}{\text{third transformation}}$

$\text{under a reflection in the x-axis}$

• " a point "(x,y)to(x,-y)

$A ' ' \left(- 9 , - 4\right) \to A ' ' ' \left(- 9 , 4\right)$

$B ' ' \left(- 7 , - 6\right) \to B ' ' ' \left(- 7 , 6\right)$

$\text{After all 3 transformations}$

$\left(4 , 9\right) \to \left(- 9 , 4\right) \text{ and } \left(2 , 7\right) \to \left(- 7 , 6\right)$