A un grupo de estudiantes del colegio Apple Valley elegidos al azar se le pidió elegir su clase de deportes favorita. La tabla siguiente muestra los resultados de la encuesta. Hay 528528528 estudiantes en el colegio Apple Valley. Clase Número de estudiantes Deportes de raqueta 111 Deportes de equipo 999 Atletismo 171717 Boliche 131313

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value

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