Assistance in College Algebra Please?

Question

I got a 95 on my test and these are the problems that I got wrong and I don't understand how. I think the teacher is wrong, but anyway, can you all work them out so I can see who's right?

Thanks in advance!


1.) x + 4/6 = 1/3 - x-3/4

2.) 27/x-2 + 3 = 18/x-2

3.) 3x +2(2x - 5) = 1 - 7x

4.) (6+4i) - (-4+i)

Answer 1

1.) x + 4/6 = 1/3 - x-3/4
2x=1/3-2/3-3/4
2x=-1/3-3/4
24x=-4-9
24x=-13

x=-13/24


2.) 27/(x-2) + 3 = 18/(x-2)

27+3x-6=18
3x=18-21
3x=-3/3=-1

x=-1/3


3.) 3x +2(2x - 5) = 1 - 7x

3x+4x-10=1-7x
7x+7x=1+10
14x=11

x=11/14


4.) (6+4i) - (-4+i)
=6+4i+4-i
=10+3i

Answer 2

Did you need parentheses for #2? The last person that answered added parentheses. If you don't put it in parentheses, your answer is -3.
27/x - 2 + 3 = 18/x -2
27/x - 18/x = -2 +2 -3
9/x = -3
9/x (x) = -3x
9 = -3x
9/-3 = -3x/-3
-3 = x

However, if it was 27 divided by the quantity of x-2 + 3 = 18 divided by the quantity of x-2, your answer would be -1.
27/(x-2) + 3 = 18/(x-2)
27/(x-2) -18/(x-2) =-3
9/(x-2) = -3
Multiply both sides by (x-2)
9 = -3x +6
9-6=-3x+6-6
3 = -3x
3/-3 = -3x/-3
-1 = x

Answer 3

1) (6x+4)/6=(4-3x+9)/12
12x+8=13-3x
15x=5
x=1/3
2) (27+3x-6)/x-2=18/x-2
3x+21=18
x=-1
3) 3x+4x-10=1-7x
14x=11
x=11/14
4) 6+4i+4-i=10+3i

Answer 4

i picked the easiest looking one, number three, and had my gf's 7th grader do it, he came up with x=11/14. I have forgotten most of my math i learned, but that doesnt seem like a college level problem, i did the other ones myself they seemed pretty basic.

Answer 5

Please correct the "apparent" oversight in problem number 4. Is it an equation, like the others? Else, ignore this observation, especially, if it is a straight problem of simplification, of the given expression.

Answer 6

R = xp R = x(100 and ten - 0.085x) R = 110x - 0.085x² 7280 = 110x - 0.085x² 0.085x² - 110x + 7280 = 0 x = ( 100 and ten +/- sqrt(100 and ten² - 4 x 0.0.5 x 7280) ) / (2 x 0.0.5) x = 1224.15 or sixty 9.ninety six Lowest such fee = $sixty 9.ninety six maximum such fee = $1224.15