# Thread: College Algebra Problems. Will +Rep!!

1. ## College Algebra Problems. Will +Rep!!

WILL +REP ANYONE THAT HELPS!
Have 4 hours to submit it and i dont know how to do any of it :/

1. Use the method of completing the square to find the standard form of the quadratic function. State the vertex and axis of symmetry of the graph of the function

f(x) = x^2 + 2x − 1

2. Use the vertex formula to determine the vertex of the graph of the function, and write the function in standard form.
f(x) = −x^2 + 6x − 1

3. Find the range of
f(x) = −x^2 − 6x − 5.

{y|y ≥ −4} or
{y|y ≤ −4} or
all real numbers or
{y|y ≤ 4} or
{y|y ≥ 4}

Determine the values of x in the domain of f for which
f(x) = 3.

4. Find the real zeros of f and the x-intercepts of the graph of f. (Enter your answers as a comma-separated list. Separate multiple ordered pairs with commas.)
f(x) = −x^2 + 8x + 9

5. Find the maximum or minimum value of the function. State whether this value is a maximum or a minimum.
f(x) = −x^2 + 16x − 7

6. Find the maximum or minimum value of the function. State whether this value is a maximum or a minimum.
f(x) = 3x^2 − 52

7. The fuel efficiency for a certain midsize car is given by
E(v) = −0.017v^2 + 1.394v + 3.8
where
E(v)
is the fuel efficiency in miles per gallon for a car traveling v miles per hour.
(a) What speed will yield the maximum fuel efficiency? Round to the nearest mile per hour.

(b) What is the maximum fuel efficiency for this car? Round to the nearest mile per gallon.

10. The function A(t) = 200e−0.014^t gives the amount of medication, in milligrams, in a patient's bloodstream t minutes after the medication has been injected into the patient's bloodstream.
(a) Find the amount of medication, to the nearest milligram, in the patient's bloodstream after 30 minutes.
mg

(b) Use a graphing utility to determine how long it will take, to the nearest minute, for the amount of medication in the patient's bloodstream to reach 50 milligrams.

11. A cup of coffee is heated to 180°F and placed in a room that maintains a temperature of 75°F. The temperature of the coffee after t minutes is given by
T(t) = 75 + 115e^−0.042t.
(a) Find the temperature, to the nearest degree, of the coffee 10 minutes after it is placed in the room.
°F

(b) Use a graphing utility to determine when, to the nearest tenth of a minute, the temperature of the coffee will reach 110°F.
After min

12. Solve the system of equations by the substitution method. (If the system is dependent, enter a general solution in terms of c. If there is no solution, enter NO SOLUTION.)

−4x + 2y = −6
x = 5y − 3

13. Solve the system of equations by the substitution method. (If the system is dependent, enter a general solution in terms of c. If there is no solution, enter NO SOLUTION.)

9x + 4y= 25
x − 5y = 30

14. Solve the system of equations by the elimination method. (If the system is dependent, enter a general solution in terms of c. If there is no solution, enter NO SOLUTION.)

5x − y = 19
5x + 3y = 3

15. Solve the system of equations by the elimination method. (If the system is dependent, enter a general solution in terms of c. If there is no solution, enter NO SOLUTION.)

3x+ 8y = 11
4x − 2y = 2

16. Solve the system of equations by the elimination method. (If the system is dependent, enter a general solution in terms of c. If there is no solution, enter NO SOLUTION.)

3x + 6y = 5
2x + 4y = 5

17. Solve by using a system of equations.

Flying with the wind, a plane traveled 420 miles in 3 hours. Flying against the wind, the plane traveled the same distance in 5 hours. Find the rate of the plane in calm air and the rate of the wind.

18. Solve the system of equations. (If the system is dependent, enter a general solution in terms of c. If there is no solution, enter NO SOLUTION.)

2x − 5y + 3z = −46
3x + 2y − z = 6
x − 3y − 4z = 2

2. I'll have a look at it..
I most likely wont have time for all of it.. But i could contribute with some answers !

3. ## The Following User Says Thank You to Dinah For This Useful Post:

kooldude888 (12-09-2012)

4. I'm extremely good at math....

All math....

Expect Algebra :c I can look through it though and see if I remember the concepts to any of them

---------- Post added at 10:19 AM ---------- Previous post was at 10:18 AM ----------

Oddly enough there's alot of what we've been doing in my class... (11th grade Algebra 2)

5. I do this kind of maths
Also my mum is a maths teacher and tutor, I'll see if I can get her to run over some or all of this stuff.
Are any of these more or less important?

6. Originally Posted by Nik
I do this kind of maths
Also my mum is a maths teacher and tutor, I'll see if I can get her to run over some or all of this stuff.
Are any of these more or less important?
More or less important? What do u mean by that?

7. There are multiple questions, some may be more important for him to know the answers for. Pretty simple.

8. 12. Solve the system of equations by the substitution method. (If the system is dependent, enter a general solution in terms of c. If there is no solution, enter NO SOLUTION.)

−4x + 2y = −6
x = 5y − 3

(So basically you just plug it it so -4(5y-3) +2y = -6 then distribute. -20y +12 +2y= -6. Then you add like terms. -20y + 2y = -18y. Get the variable alone -12 from each side. So now it looks like -18y = -18 . Divide each side by -18. Which gets you 1 )
I think :c Someone double check my work

9. ## College Algebra Problems. Will +Rep!!

Man I just realised you need to submit this within 4 hours and it's really late where I am so I can't really help

10. I know it's too late but I can show you how to do one at least.

15. Solve the system of equations by the elimination method. (If the system is dependent, enter a general solution in terms of c. If there is no solution, enter NO SOLUTION.)

1. 3x+ 8y = 11
2. 4x − 2y = 2

x=(11-8y)/3 //rewrite to isolate one variable, doesn't matter which equation or variable
4[(11-8y)/3] - 2y= 2 //plug back into other equation to get only one variable
(44-32y)/3 - 2y = 2 //simplify
(44-32y)/3 - (6y/3) = 2 //combine like terms
(44-38y)/3= 2 //simplify cont.
3*[(44-38y)/3= 2] //remove denominator
44-38y = 6 //simplify cont.
-38y = -38 //simplify cont.
y = -1 //simplify cont.

Now, plug back into any of the original equations to find x.
3x+ 8(-1) = 11 //plug in y-value
3x=11+8 //simplify
x= 6.333333 //solve

And then do it the other to check if there are other solutions:

2y = -2+4x
y = 2x-1
3x+(8)(2x-1)=11
3x+16x-8=11
x=1

So your points are (-1,6.33) and (1,1)
If you have a graphing calculator you can plot the two lines and find the intersections to double check.

11. ## The Following User Says Thank You to Graff For This Useful Post:

kooldude888 (12-09-2012)

12. @kooldude888
If you PM me I can usually get to homework stuff quickly . Hopefully you were able to submit this on time, though . I can show all the methods of solving, though

13. ## The Following User Says Thank You to Reese For This Useful Post:

kooldude888 (12-09-2012)

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