# the equation of a straight line is 3x+2y=11. find the equation of a parrallel line pa

• Oct 13th 2008, 10:00 AM
coyoteflare
the equation of a straight line is 3x+2y=11. find the equation of a parrallel line pa
i made it y=-3/2 x +11.5

but i think its wrong help
• Oct 13th 2008, 10:04 AM
masters
Quote:

Originally Posted by coyoteflare
i made it y=-3/2 x +11.5

but i think its wrong help

$3x+2y=11$

Transpose (move) the 3x to the right side of the equation, thus changing its sign.

$2y=-3x+11$

Divide each term by 2

$y=-\frac{3}{2}x+\frac{11}{2}$
• Oct 13th 2008, 10:06 AM
coyoteflare
Quote:

Originally Posted by masters
$3x+2y=11$

Transpose (move) the 3x to the right side of the equation, thus changing its sign.

$2y=-3x+11$

Divide each term by 2

$y=-\frac{3}{2}x+\frac{11}{2}$

but surely you have to substitute 5,4 in somewhere?
• Oct 13th 2008, 10:10 AM
masters
Quote:

Originally Posted by coyoteflare
but surely you have to substitute 5,4 in somewhere?

I'm sorry. I'm not seeing the rest of your question.....

Are you trying to find the equation of a line through (5,4) that is parallel to $y=-\frac{3}{2}x+\frac{11}{2}$?
• Oct 13th 2008, 10:11 AM
coyoteflare
yeh :D thats what im after [:
• Oct 13th 2008, 10:16 AM
masters
If that be the case, then we will use the same slope as:

$y=-\frac{3}{2}x+\frac{11}{2}$ which is $-\frac{3}{2}$

We need to find the y-intercept. Use the slope-intercept form of the linear equation and use the point given (5, 4).

$y=mx+b$

$4=-\frac{3}{2}(5)+b$

$4=-\frac{15}{2}+b$

$\frac{23}{2}=b$

Substituting back into y=mx+b, we have

$y=-\frac{3}{2}x+\frac{23}{2}$