Identify the value of C for completing the square X^2– 16x + c

A) 16
B) 64
C) -64
D) -16

the function makes a strait line horizontally with no x intercept but a y intercept at 9.

ummm seems that u didnt post the attachement !

i think it might be a but you might want a second opinion

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