What is the simplest form of the expression (14.2a + 9.8b) – (13.1b – 0.2a) – (3.7a + 4.8b)?
10.7a – 8.1b
10.7a Plus 27.7b
18.1a Minus 8.1b
18.1a Plus 27.7b

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4

it would open into a square depending on the type of envelope i’m not sure about the second part

for future students the answer is b

hope i

-lavira: )