Answer:
8/10 hahahshshshdhdhdbdbd
First you can solve for b: Subtract a on both sides and get 2b=-a+10, then divide by 2 to get b by itself and get: b=-1/2a+5
Then you can plug in this equation for b in the other: This would give you: 2a+-1/2a+5=6. Then you can use that equation to solve for a and get: 1.5a+5=6, subtract 5, 1.5a=1, divide by 1.5, a=1/1.5
Then you can plug in the value of a to solve for b.
angles EFH and GFH are congruents
for the second equivalence criterion two triangles are equivalents if they have respectively 2 angles and 1 side congruents
the two triangles have congruents the angle right angle (HGF and HEF) and the 55 degrees angles (EFH and GFH); then they have in common the HF side.
so the triangles are congruent and so all the sides are respectively congruent,for example EH with HG:
EH=HG
s+36=7s
s+36-7s=0
s-7s=-36
-6s=-36
6s=36
s=6
<em>sorry for my english</em>