PDA

View Full Version : Algebra help! - test tomorrow! (help!)


kerensak
May 29, 2006, 12:41 PM
There are a few problems that I am having trouble with. I hope someone can help me figure them out (& please explain how you got them).

Robin is having her yard landscaped. She obtained an estimate from two landscaping companies. Company A gave an estimate of $210 for materials and equipment rental plus $65 per hour for labor. Company B gave an estimate of $280 for materials and equipment rental plus $55 per hour for labor. Determine how many hours of labor will be required for the two companies to cost the same.
EDIT: I got 7 hours.
x=hours
210 + 65x = 280 +55x
10x = 70
x=7



I absolutely hate these:
The formula F = 18t2 - 200t + 938 models the number of convicts in a city t years after 1985. How many convicts were there in 1995?



Usually I have no problem with these but I've worked it like five times:
Find (fg)(-5) when f(x) = x+4 and g(x)=4x2+18x-1
Edit: I got an answer.

(x+4)(4x2 +18x-1)
4x3+18x2-x+16x+72x-4

4(-5)^3 + 18(-5)^2 - (-5) + 16(-5)^2 + 72(-5) - 4
-500 + 450 +5 + 400 - 360 - 4
=-9


The answers are either:
-9, -81, 66, -891


Last, but not least:
The length of a rectangular room is 6 feet longer than twice the width. If the room's perimeter is 144 feet, what are the room's dimensions?
EDIT: I got the answer

x=width
x+6=length

2(x+6) + 2x = 144
2x + 12 + 2x = 144
4x = 132
x = 33

33 + 6 = 39 (LENGTH
33ft x 39ft



Find the domain of f/g when f(x) =4x2 + 4x - 4 and g(x) = x-2
Edit: I found the answer

{x|x is a real number and x does not equal 2}


MOST IMPORTANTLY, I JUST WANT TO KNOW HOW TO GET TO THE ANSWER. JUST GIVING ME THE ANSWERS AREN'T GOING TO HELP. :eek:

CaptainForest
May 29, 2006, 01:53 PM
Robin
Correct, 7 hours

Convicts in City
F = 18t2 - 200t + 938

the number of convicts in a city t years after 1985

in 1995 = ?

1995 is 10 years after 1985

So,
F = 18t2 - 200t + 938
F = 18(10)2 – 200(10) + 938
F = 738

Therefore, there were 738 convicts there in 1995.

Rectangle Room
Length = 2w + 6

Perimeter = 144

144 = 2w + 6 + 2w + 6 + w + w
144 = 6w + 12
6w = 132
w = 22

Therefore, the width is 22 feet, the length is 22x2 + 6 = 50 feet

Perimeter = 50 + 50 + 22 + 22 = 144

Therefore, the dimensions are

Width = 22 feet
Length = 50 feet

fredg
May 30, 2006, 06:20 AM
Hi,
I might suggest that don't do as I did when in high school; don't wait until the day before to try learning how to do Algebra. I was a High School math teacher for 13 yrs, teaching among other subjects, Algebra.
I had "extra help" classes for students after school, and many, many took advantage of it. Please talk with your teacher about getting some help, or maybe he/she can suggest someone who can help you.
Best of luck.