math questions?

Question

does nebody no how to do these problems

3a-4=a+8
2n-5=1/2n+4

Answer 1

3a-4=a+8
subtract a from both sides and add 4 to both sides
you'll end up with
2a = 12
divide both sides by 2
a = 6

2n-5=1/2n+4
multiply both sides by 2n (to get rid of the fraction 1/2n)

2n(n-5) = 2n(1/2n + 4) Use the distributive property
2n^2 - 10n = 1 + 8 n
Move everything to the left side of the equal sign by subracting 1 from both side and subractin 8n from both sides

2n^2 -18n - 1 = 0 Now you have a quadratic equation

Answer 2

1. 3a-4=a+8
first subtract a from 3a. (since you take it to the other side you do the opposite function of what a is) for instance: a is positive, so it needs to be subtracted from the other side.
3a-a=2a
now the equation reads: 2a-4=8.
from here, take the (-4) to the other side where it should be added to eight. (again, doing the opposite function)
2a=12; therefore, a=6.
To check the answer you can plug in 6 for a:
3(6)-4=6+8.

2. 2n-5=1/2n+4
This problem calls for the same concept. First take the 1/2n to the other side. The opposite of +1/2n is -1/2n. 2n-1/2n=1 1/2n or 1.5n. Now the problem reads:
1.5n-5=4
Add 5 to the 4 on the opposite side (because +5 is the opposite of -5). 1.5n=9
n=6. Plug in 6 when the n is in the original equation to check your answer.

Hope this helps!

Answer 3

Lets do 3a-4=a+8
U hav to put all d 'a's on the left hand side...
therefore, 3a-a=4+8 (the signs change as you change sides)
2a=12
a=12/2
a=6

Now for 2n-5=1/2n+4
2n-1/2n=4+5
1.5n=9
n=9/1.5
n=6

As the numbers change sides, a positive number becomes negative and vice versa.
And where a multiplication sign is understood (that is between 1/2 and 'n' the second equation), when u change sides, it changes to a division sign...
hope you understand.

Answer 4

move the a's to one side and everything else on the other, then solve:

3a-a=4+8
2a=12
a=6

2n-1/2n=4+5
3/2n=9
3n=18
n=6

Answer 5

3a-4=a+8
2a-4=8
2a=12
a=6

2n-5=.5n+4
1.5n-5=4
1.5n=9
n=6