# linear equation problem (again)

• Aug 10th 2009, 08:43 PM
brainfreeze
linear equation problem (again)
3y+4= y/2+9

how do i do this?! im confused :(
• Aug 10th 2009, 08:49 PM
HallsofIvy
Quote:

Originally Posted by brainfreeze
3y+4= y/2+9

how do i do this?! im confused :(

Get the "unknown" (in this case y) by itself on one side of the equation. Here, you might start by getting both "y"s on the left and anything not involving "y" on the right. Since there is a "y/2" added on the left, do the opposite: subtract y/2 from both sides: 3y+ 4- y/2= y/2+ 9- y/2 becomes (3- 1/2)y+ 4= 9 or (6/2- 1/2)y+ 4= (5/2)y+ 4= 9. Now subtract 4 from both sides: (5/2)y+ 4- 4= 9- 4 or (5/2)y= 5. Since y is now multiplied by 5/2, do the opposite: divide both sides by 5/2 (or, same thing, multiply both sides by 2/5): (2/5)(5/2)y= (2/5)(5) or y= 2.
• Aug 10th 2009, 09:32 PM
brainfreeze
thanks, but im stuck again lol,

3/4t= -1 7/8

ive tried to move 7/8 to the other side,
but only to fail.
this is what keeps happening

3/4t= -1 7/8
(3/4÷7/8)t = -1

my answer keeps coming up t=-1 1/6
but the answer is -2 1/6

now i know ive done something wrong
but im not sure what it is lol
• Aug 10th 2009, 11:34 PM
SENTINEL4
$\displaystyle \frac{3}{4}t=-\frac{7}{8}$ Is this the problem you want to solve?
• Aug 11th 2009, 02:57 AM
brainfreeze
thats exactly what im trying to solve
• Aug 11th 2009, 04:00 AM
mr fantastic
Quote:

Originally Posted by SENTINEL4
$\displaystyle \frac{3}{4}t=-\frac{7}{8}$ Is this the problem you want to solve?

Quote:

Originally Posted by brainfreeze
thats exactly what im trying to solve

@OP: Start by multiplying both sides of the equation by 8:

6t = -7.