The name of this property is symetric property of equality
2x+4=3x+1 they've substituted y =2x+4 into the second eq.
10/4
To get then watts per panel
550 / the Watts per panel to get the number of panels need
Always round this up if necessary
Answer:
Use the Pyth. Theorem

c being the Hypotenuse (x)

= 25
<em>Hope this helps!!!</em>
