Which two expressions are equivalent? A. 4 + (3 •y) and (4 + 3) • y
B. (18 = y) + 10 and 10 + (y - 18)
C. 12 - (y • 2) and 12 – (2•y)
D. (10 - 6) + y and 10 – (6 = y)

the answer will be b x² +x-1

step-by-step explanation:

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