Can someone show me please? C:
The equation -5x² + 72x + 378 models the number of students enrolled in a school where x is the number of years since the school first opened in 1990. How many students did the school have when it opened?
a) 68
b) 72
c) 445
d) 378

Question

Can someone show me please? C:
The equation -5x² + 72x + 378  models the number of students enrolled in a school where x is the number of years since the school first opened in 1990. How many students did the school have when it opened?
a) 68
b) 72
c) 445
d) 378

primeralph · Answer

Put x = 0.

campbell_st · Answer

well if x is the number of years since opening, so if you are looking at the intitial population substitute x =0 and evaluate

anonymous · Answer

so then.. the equation would become -5x²+378 because we substituted the x with 0 and 72 multiplied by 0 is 0. Right? Then evaluate from there??

campbell_st · Answer

no if you substitute x = 0 you get

$$-5(0)^2 + 72(0) + 378$$

what does that equal..?

anonymous · Answer

plug in 0

anonymous · Answer

all the terms become zero except for the constant term ;)

anonymous · Answer

D ._.

anonymous · Answer

378

anonymous · Answer

-5x² + 72x + 378
-5*0² + 72*0 + 378

0         +       0        + 378   = 378 :P