# Pls help me on this during the rainy season

By lonely_f16

@lonely_f16 (2147)

Philippines

July 7, 2007 11:51pm CST

the southwest of Metro Manila received heavy rain. The water level of a flooded area was 75 cm deep, and dropped by 3 cm/hr after the heavy rain stopped. Let x represent the number of hours and f(x) represent the water's height.
a.) Form the equation in functional notation.
b.) Set up the table of values for x and f(x)
c.) Why is it not necessary to choose negative values for x?
please help me answer this...thanks!

1 person likes this

2 responses

@migenKC (792)

• Philippines

8 Jul 07

i cant remember how to make an equation in functional notation buy hope i can help you on this...
on your number 3 question... its not necessary since x represents time.. there is no such thing as negative one hour... a time doesnt go back but continues to go forward... did you get it?
on your 2nd question... its hard to expalin it to you coz i need to draw lines...
hmp... what can i do?
i guess its somethin like this...(since you're a Filipino.. let me expalain it to you on tagalog... is it ok?
mag lagay ka ng dalawang rows... sa left side naga represent ng x values... while sa right side... naga represent ng f(x)..sa gitna isang line...
bale ibig sabihin if 0 ang x... ang equivalent nya sa f(x) ay 75 since di pa naman nababwasan ang water... then... if 1 ang x... ang equivalent nya sa f(x) ay 72 since nabawasan na ng 3cm ang water... then.. if 2 ang x... ang equivalent nya sa f(x) ay 69 since nabawasan na ulit ng 3cm.... and so on.. every after an hour nababawasan ang water ng 3 cm... ayun... ahihi...
di ko lang mabigay ang equation... nalimutan ko na kasi pano mag form... ang tagal ko na kasi na lesson.. anong year ka na? ahihi.. nag tagalog na ako... :)

1 person likes this

@beauty_ph (2751)

• Philippines

10 Jul 07

the southwest of Metro Manila received heavy rain. The water level of a flooded area was 75 cm deep, and dropped by 3 cm/hr after the heavy rain stopped. Let x represent the number of hours and f(x) represent the water's height.
I know how to answer this:
a.) Form the equation in functional notation.
f(x)=75-3x
b.) Set up the table of values for x and f(x)
f(x) x
75 0
72 1
69 2
c.) Why is it not necessary to choose negative values for x? Time is never negative. Also if choose a negative value for x, instead of seeing the depth of water to drop it goes up which makes the statement false.
Do you think I get it right?