Answer:
-30
Step-by-step explanation:
Hope this helps!
The distance from point Y to the y-axis is 4 units and the distance from point Z to the y-axis is 3 units, then the lelgth of the segment YZ is 4+3=7 units.
If <span>a scale factor is 3, then the length of Y'Z' will be 7·3=21 units.
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P.S. In the added picture you can see trapezoid ABCD that was dilated by a scale factor 3 about the origin. This may help to understand that all linear values after dilation become multiplied by scale factor.
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The first graph is what i would think