Question

WILL GIVE A MEDAL
What is the image of (-1, 1) after a dilation of 2?

(1, 3)
(-2, 2)
(2, 2)

Answer 1

hint:
the matrix which represent that dilation is:
\[A = \left( {\begin{array}{*{20}{c}}
2&0 \\
0&2
\end{array}} \right)\]

Answer 2

are you familiar with matrices?

Answer 3

I am not.

Answer 4

by definition, if x' and y' are the new coordinates, namely the coordinates of the point after a dilation, and x and y are the old coordinates, then we can write:
\[\large \begin{gathered}
x' = 2x \hfill \\
y' = 2y \hfill \\
\end{gathered} \]
where x=-1 and y=1
so, what are x' and y' ?

Answer 5

I don't know. I'm sorry, I don't understand this.

Answer 6

we have to replace x with -1, and y with 1:
\[\large \begin{gathered}
x' = 2x = 2 \times \left( { - 1} \right) = ...? \hfill \\
y' = 2y = 2 \times 1 = ...? \hfill \\
\end{gathered} \]

Answer 7

x' = -2
y' = 2

Answer 8

that's right! So what is the right option?

Answer 9

B. So that's how you do these?

Answer 10

correct! The right option is B. and yes! the procedure above is how to solve your exercise

Answer 11

Thank you so much. :)

Answer 12

Thank you! :)