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| Question 34311:  Write the equatin of the line L satisfying the given geometric conditions:
 L has y-intercept (0,2) and is perpendicular to the line with equation 2x-3y=6
 Answer by venugopalramana(3286)
      (Show Source): 
You can put this solution on YOUR website! OK I AM ANSWERING BELOW Write the equatin of the line L satisfying the given geometric conditions:
 L has y-intercept (0,2) and is perpendicular to the line with equation 2x-3y=6
 EQN.OF LINE PERPENDICULAR TO ABOVE LINE IS
 2Y+3X=K..(INTERCHANGE X AND Y COEFFICIENTS AND CHANGE SIGN AND EQUATE TO A CONSTANT TO BE FOUND)
 IT PASSES THROUGH....(0,2)..SO
 2*2+3*0=K
 K=4
 SO EQN. OF PERPENDICULAR LINE IS
 2Y+3X=4
 SEE THE FOLLOWING WHICH IS SIMILAR TO YOUR PROBLEM AND DO
 GIVEN:
 · There is a line (L1) that passes through the points
 (8,-3) and (3,3/4).
 · There is another line (L2) with slope m=2/3 that
 intersects L1 at the point (-4,6).
 · A third line (L3) is parallel to L2 that passes
 through the (7,-13 1/2).
 · Yet another line (L4) is perpendicular to L3, and
 passes through the point (1/2,5 2/3).
 · The fifth line (L5) has the equation
 2/5y-6/10x=24/5.
 Using whatever method, find the following:
 2. The point of intersection of L1 and L3
 3. The point of intersection of L1 and L4
 4. The point of intersection of L1 and L5
 5. The point of intersection of L2 and L3
 6. The point of intersection of L2 and L4
 7. The point of intersection of L2 and L5
 8. The point of intersection of L3 and L4
 9. The point of intersection of L3 and L5
 10. The point of intersection of L4 and L5
 PLEASE NOTE THE FOLLOWING FORMULAE FOR EQUATION OF A
 STRAIGHT LINE:
 slope(m)and intercept(c) form...y=mx+c
 point (x1,y1) and slope (m) form...y-y1=m(x-x1)
 two point (x1,y1)and(x2,y2)form.....................
 y-y1=((y2-y1)/(x2-x1))*(x-x1)
 standard linear form..ax+by+c=0..here by transforming
 we get by=-ax-c..or y=(-a/b)x+(-c/b)..comparing with
 slope intercept form we get ...slope = -a/b and
 intercept = -c/b
 *****************************************************
 line (L1) that passes through the points (8,-3) and
 (3,3/4).
 eqn.of L1..y-(-3)=((3/4+3)/(3-8))*(x-8)
 y+3=((15/4(-5)))(x-8)=(-3/4)(x-8)
 or multiplying with 4 throughout
 4y+12=-3x+24
 3x+4y+12-24=0
 3x+4y-12=0.........L1
 There is another line (L2) with slope m=2/3 that
 intersects L1 at the point (-4,6).
 This means (-4,6)lies on both L1 and L2.(you can check
 the eqn.of L1 we got by substituting this point in
 equation of L1 and see whether it is satisfied).So
 eqn.of L2...
 y-6=(2/3)(x+4)..multiplying with 3 throughout..
 3y-18=2x+8
 -2x+3y-26=0.........L2
 A third line (L3) is parallel to L2 that passes
 through the (7,-13 1/2).
 lines are parallel mean their slopes are same . so we
 keep coefficients of x and y same for both parallel
 lines and change the constant term only..
 eqn.of L2 from above is ...-2x+3y-26=0.........L2
 hence L3,its parallel will be ...-2x+3y+k=0..now it
 passes through (7,-13 1/2)=(7,-13.5)......substituting
 in L3..we get k
 -2*7+3*(-13.5)+k=0...or k=14+40.5=54.5..hence eqn.of
 L3 is........-2x+3y+54.5=0......................L3
 Yet another line (L4) is perpendicular to L3, and
 passes through the point (1/2,5 2/3).
 lines are perpendicular when the product of their
 slopes is equal to -1..so ,we interchange coefficients
 of x and y from the first line and insert a negative
 sign to one of them and then change the constant term.
 L3 is........-2x+3y+54.5=0......................L3
 hence L4,its perpendicular will be ..3x+2y+p=0...L4
 this passes through (1/2,5 2/3)=(1/2,17/3).hence..
 3*1/2+2*17/3+p=0..or ..p= -77/6.so eqn.of L4 is
 3x+2y-77/6=0..............L4
 The fifth line (L5) has the equation 2/5y-6/10x=24/5.
 now to find a point of intersection means to find a
 point say P(x,y) which lies on both the lines ..that
 is, it satisfies both the equations..so we have to
 simply solve the 2 equations of the 2 lines for x and
 y to get their point of intersection.For example to
 find the point of intersection of L1 and L3 we have to
 solve for x and y the 2 equations....
 3x+4y-12=0.........L1....(1) and
 -2x+3y+40.5=0......L3.....(2)
 I TRUST YOU CAN CONTINUE FROM HERE TO GET THE
 ANSWERS.If you have any doubts or get into any
 difficulty ,please ask me.
 Graphs/24461: find the slope,m,and the y intercept,b,of the line whose equation is 4x+2y+8=0
 1 solutions
 Answer 13032 by venugopalramana(1088) About Me  on 2006-01-15 10:52:29 (Show Source):
 SEE THE FOLLOWING WHICH IS SIMILAR TO YOUR PROBLEM AND DO
 GIVEN:
 · There is a line (L1) that passes through the points
 (8,-3) and (3,3/4).
 · There is another line (L2) with slope m=2/3 that
 intersects L1 at the point (-4,6).
 · A third line (L3) is parallel to L2 that passes
 through the (7,-13 1/2).
 · Yet another line (L4) is perpendicular to L3, and
 passes through the point (1/2,5 2/3).
 · The fifth line (L5) has the equation
 2/5y-6/10x=24/5.
 Using whatever method, find the following:
 2. The point of intersection of L1 and L3
 3. The point of intersection of L1 and L4
 4. The point of intersection of L1 and L5
 5. The point of intersection of L2 and L3
 6. The point of intersection of L2 and L4
 7. The point of intersection of L2 and L5
 8. The point of intersection of L3 and L4
 9. The point of intersection of L3 and L5
 10. The point of intersection of L4 and L5
 PLEASE NOTE THE FOLLOWING FORMULAE FOR EQUATION OF A
 STRAIGHT LINE:
 slope(m)and intercept(c) form...y=mx+c
 point (x1,y1) and slope (m) form...y-y1=m(x-x1)
 two point (x1,y1)and(x2,y2)form.....................
 y-y1=((y2-y1)/(x2-x1))*(x-x1)
 standard linear form..ax+by+c=0..here by transforming
 we get by=-ax-c..or y=(-a/b)x+(-c/b)..comparing with
 slope intercept form we get ...slope = -a/b and
 intercept = -c/b
 *****************************************************
 line (L1) that passes through the points (8,-3) and
 (3,3/4).
 eqn.of L1..y-(-3)=((3/4+3)/(3-8))*(x-8)
 y+3=((15/4(-5)))(x-8)=(-3/4)(x-8)
 or multiplying with 4 throughout
 4y+12=-3x+24
 3x+4y+12-24=0
 3x+4y-12=0.........L1
 There is another line (L2) with slope m=2/3 that
 intersects L1 at the point (-4,6).
 This means (-4,6)lies on both L1 and L2.(you can check
 the eqn.of L1 we got by substituting this point in
 equation of L1 and see whether it is satisfied).So
 eqn.of L2...
 y-6=(2/3)(x+4)..multiplying with 3 throughout..
 3y-18=2x+8
 -2x+3y-26=0.........L2
 A third line (L3) is parallel to L2 that passes
 through the (7,-13 1/2).
 lines are parallel mean their slopes are same . so we
 keep coefficients of x and y same for both parallel
 lines and change the constant term only..
 eqn.of L2 from above is ...-2x+3y-26=0.........L2
 hence L3,its parallel will be ...-2x+3y+k=0..now it
 passes through (7,-13 1/2)=(7,-13.5)......substituting
 in L3..we get k
 -2*7+3*(-13.5)+k=0...or k=14+40.5=54.5..hence eqn.of
 L3 is........-2x+3y+54.5=0......................L3
 Yet another line (L4) is perpendicular to L3, and
 passes through the point (1/2,5 2/3).
 lines are perpendicular when the product of their
 slopes is equal to -1..so ,we interchange coefficients
 of x and y from the first line and insert a negative
 sign to one of them and then change the constant term.
 L3 is........-2x+3y+54.5=0......................L3
 hence L4,its perpendicular will be ..3x+2y+p=0...L4
 this passes through (1/2,5 2/3)=(1/2,17/3).hence..
 3*1/2+2*17/3+p=0..or ..p= -77/6.so eqn.of L4 is
 3x+2y-77/6=0..............L4
 The fifth line (L5) has the equation 2/5y-6/10x=24/5.
 now to find a point of intersection means to find a
 point say P(x,y) which lies on both the lines ..that
 is, it satisfies both the equations..so we have to
 simply solve the 2 equations of the 2 lines for x and
 y to get their point of intersection.For example to
 find the point of intersection of L1 and L3 we have to
 solve for x and y the 2 equations....
 3x+4y-12=0.........L1....(1) and
 -2x+3y+40.5=0......L3.....(2)
 I TRUST YOU CAN CONTINUE FROM HERE TO GET THE
 ANSWERS.If you have any doubts or get into any
 difficulty ,please ask me.
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