Question

expand and simplify where appropriate
(x-8)^2

Answer 1

HELPPPP

Answer 2

(x-8)(x-8)
= x ^2 -8x+ (-8x) (-)-8^2
= x^2 - 16x + 64

Answer 3

is that what you need to do O. o?

Answer 4

yeah, i did it again and got that but i didnt know if it was right.. thanks heaps

Answer 5

:D you are welcome~

Answer 6

i have another question. Do you know how to do parabolas??

Answer 7

um, i will try :D

Answer 8

ok, because i keep doing something wrong and i was just wondering if you could do the equation so i could see where i went wrong.. if thats not asking too much??

Answer 9

yeah, sure, i will do my best XD

Answer 10

ok, thanks. heres the question..

Answer 11

ok

Answer 12

Over a period of 8hours, the temperature of a room follows the relationship T=h^2-6h+15 where T is the temperature in degrees Celcius, h hours after commencing the experiment
a) Sketch the graph of this quadratic relationship
b) What is the initial temperature?
c) After 2 hours, is the temperature of the room increasing or decreasing?
d) After 6 hours is the temperature of the room increasing or decreasing?
e) Find the minimum temperature
f) When did the minimum temperature occur?
Sorry, it's alot :(

Answer 13

wait XD

Answer 14

a) y intercept : h=0
T=y
y= 0^2 - 6(0) + 15
= 15



i think the initial temperature will be the y intercept (0, 15) for the hours(x/ h)can not be negative
c) T = (2)^2 - 6(2) + 15 (sub in or look at the graph)
= 4 - 12 +15
= 7 (which mean decrease)

d) same sub in or look at the graph
T = (6)^2 - 6(6) + 15
= 36 - 36 + 15
= 15 (which mean it stay the same ( so it goes decrease at h = 7 and slowly go back up and h=6 will be back to the start temperature )

e) the minimum is the turning point
which is
T = x^2 - 6h + 15
= (x^2-6x+9) + 6
= (x - 3)^2 + 6

TP: (3, 6)