Answer:
<h2>The lengths of the bases of the trapezoid:</h2><h2>
42/h cm and 84/h cm.</h2>
Step-by-step explanation:
The formula of an area of a triangle:

<em>b</em><em> </em>- base
<em>h</em> - height
We have <em>b = 21cm, h = 6cm</em>.
Substitute:

The formula of an area of a trapezoid:

<em>b₁, b₂</em> - bases
<em>h</em><em> - </em>height
We have <em>b₁ = 2b₂</em>, therefore <em>b₁ + b₂ = 2b₂ + b₂ = 3b₂</em>.
The area of a triangle and the area of a trapezoid are the same.
Therefore
<em>multiply both sides by 2</em>
<em>divide both sides by 3</em>
<em>divide both sides by h</em>


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.
</span>
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.
<span> </span>
Answer:
Y-3 = 2(x+1)
open the brackets
Y-3 = 2x+2
Y = 2x+5..... this is the answer when solving for Y
if were solving for x:
Y-3 = 2x+5
Y-8 = 2x
