Help!!! I have 3 math questions 10 pts please??

Question

1. Find the prodct:
(0.0028x + 0.38)(0.4x + 0.46)


2. The polynomial function I(t) = -.1t^2 + 1.9t represents the yearly income (or loss) from a real estate investment, where t is time in years. After what year does incomebegin to decline?

Year 19, Year 8.5, Year 9.5, or Year 12.67 ?????

3. Add or subtract as indicated:
(5x^5 + 2x^7 - 7+4x^6) - (9 - 9x^6 + 7x^7 -7x^5)


I would greatly appreciate some help with these because I'm totally stumped.

Sorry I put an extra zero in the problem! It should be: (0.028x + 0.38)(0.4x + 0.46)

Answer 1

1)well, the first one is just the distributive property

surely you have multiplied lots of these statements of the form
(ax+b)(cx+d)
this is just the same, it doesn't change anything because the numbers are decimal fractions

FOIL (does that seem famaliar to you?, if not, you need to start back at the beginning of the chapter)

[firsts].0028x*.4x+ [outsides](.0028x*.46)+[insides] ....you know?
if you have a computer with windows then you have a calculator and thats all you need to just knock this first one out

2) the easy way to do number 2 is with calculus, but since you couldn't do number 1, I'm guessing calculus is still in your future

i think that the wording must be wrong and instead of wanting to know when the income begins to decline, they want to know when income begins to be negative, that makes it an algebra problem

you can see that the function has a negative term and a positive term, and if the positive term is bigger the answer is positive and there is income, and if the negative term is bigger then there is "loss"

-.1t^2 and 1.9t

since the t in the negative term is squared it is getting bigger faster than the other term

at t=1, the first term = -.1 and the second term=1.9, so the positive term is bigger, as t gets bigger, the first term will get bigger faster and at one point the two terms will be equal and then after that, the negative term will be bigger and the function will go negative

where is that point where they are equal (when the function is zero before it goes negative)

set the two terms equal to each other and solve for t, to find out what value of t makes them equal

.1t^2=1.9t
.1t=1.9
t=19

so, at t=19, the yearly income is zero, and in years after that the income is negative, a loss

so, after what year does it start to be a loss?
19

if you ansered the question as it was asked, the answer would be year one, the first year is the highest income and it declines after that

3) this one is straightforward algebra
remember to distribute the minus sign to all the terms in the second parenthetical statement -9+9x^2-7x^7 etc

gather all the like terms together (that means get all the x^7 together and all the numbers with no x in the term) and add all the like terms

you can't add any x^7's to x^6's, just like terms

add all the like terms and your done (watch the signs carefully and you will be alright)

good luck

Answer 2

1. 0.00112x^2 + 0.153288x + 0.1748

2. 9.5 years

3.
(5x^5 + 2x^7 - 7+4x^6) - (9 - 9x^6 + 7x^7 -7x^5)
5x^5 + 2x^7 - 7+4x^6 - 9 + 9x^6 - 7x^7 +7x^5
-5x^7 + 13x^6 + 12x^5 - 16

Answer 3

0.00112x² + 0.153288x + 0.1748

year 9.5

-5x^7 + 13x^6 + 12x^5 - 16

Answer 4

You should separate these into three different questions. They're really worth ten points each.

Answer 5

1) 00.46.0
2) idk
3) 47.77

im completly honest i know 1 & 3 r right

Answer 6

If you can't figure these out on your own how do you expect to pass the test on it?

Answer 7

Stop relying on others for your intelligence. Do your own homework.

Answer 8

These are the easiest questions i have seen yet.
LOL. If you can't do these, you'll flunk for sure.