Answer:
every U.S dollar is worth 16 Mexican pesos
80 km = 80000 m
5 saatte = 300 dk’dir
80000m/300 dk’dir = 266.666667 m/dk’dir
(Yazım yanlışsa kusura bakmayın türkçe bilmiyorum :) )
The illegal values of b are when the denominator equals 0.
So,
gives you (b-4)(b+2)=0
Therefore, b=4 and b=-2, which is answer A.
The vertex and the t-intercept where t>0, will help solve this problem. Sending the work on the attachment.