Evaluate the function f(x) = x/3+4 for f(-9).
a. -23
b. -2
c. 7
d. 1

d. 1

Step-by-step explanation:

To evaluate a function, plug the number in the parentheses into the expression in place of x:

(-9/3) + 4 = 1

the line of

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