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  1. #1
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    the equation of a straight line

    the equation of stralight line is 3x+2y=11 find the equation of the parrallel line passing through the point 2,5

    i got y=2/3x +7 1/3

    or is it y=2/3x -4.5
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  2. #2
    A riddle wrapped in an enigma
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    Quote Originally Posted by coyoteflare View Post
    the equation of stralight line is 3x+2y=11 find the equation of the parrallel line passing through the point 2,5

    i got y=2/3x +7 1/3

    or is it y=2/3x -4.5
    $\displaystyle 3x+2y=11$

    $\displaystyle 2y=-3x+11$

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

    Slope(m) = $\displaystyle -\frac{3}{2}$

    Use slope-intercept form of the linear equation: y=mx+b and (2, 5) and solve for b.

    $\displaystyle y=mx+b$

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

    $\displaystyle 5=-3+b$

    $\displaystyle 8=b$

    Substituting back into y=mx+b, we have:

    $\displaystyle y=-\frac{3}{2}x+8$
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  3. #3
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    Quote Originally Posted by coyoteflare View Post
    the equation of stralight line is 3x+2y=11 find the equation of the parrallel line passing through the point 2,5

    i got y=2/3x +7 1/3

    or is it y=2/3x -4.5
    The LHS of the equation of the parallel must be 3x + 2y too. To calculate the RHS you only have to plug in the coordinates of the given point. Thus the equation of the parallel is:

    $\displaystyle \boxed{3x+2y=16}$
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  4. #4
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    i feel so stupid sorry i meant..

    Quote Originally Posted by masters View Post
    $\displaystyle 3x+2y=11$

    $\displaystyle 2y=-3x+11$

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

    Slope(m) = $\displaystyle -\frac{3}{2}$

    Use slope-intercept form of the linear equation: y=mx+b and (2, 5) and solve for b.

    $\displaystyle y=mx+b$

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

    $\displaystyle 5=-3+b$

    $\displaystyle 8=b$

    Substituting back into y=mx+b, we have:

    $\displaystyle y=-\frac{3}{2}x+8$
    ..perpendicular.. sorry not parrallel...

    getting confused cus im trying to do binomials too
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  5. #5
    A riddle wrapped in an enigma
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    Quote Originally Posted by coyoteflare View Post
    ..perpendicular.. sorry not parrallel...

    getting confused cus im trying to do binomials too
    In that case, just change the slope to $\displaystyle \frac{2}{3}$ which is the negative reciprocal of $\displaystyle -\frac{3}{2}$ and then proceed the same way.

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

    $\displaystyle 5=\frac{4}{3}+b$

    $\displaystyle \frac{11}{3}=b$

    The equation of the perpendicular is $\displaystyle y=\frac{2}{3}x+\frac{11}{3}$
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