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Question 481674: 1. Write an equation of the line containing the given point and parallel to the given line.
(-5,2); 4x=5y+7
The equation of the line is y=__________
Express your answer in the form y=mx+b.
2.Write an equation of the line containing the given point and perpendicular to the given line.
(4,8); 9x+y=8
The equation of the line is y=__________
Express your answer in the form y=mx+b.
Please help, I have tried solving it and keep getting it wrong!
Answer by mananth(16949)   (Show Source):
You can put this solution on YOUR website! 1. Write an equation of the line containing the given point and parallel to the given line.
(-5,2); 4x=5y+7
4 x -5 y = 7
Find the slope of this line
make y the subject
-5 y = -4 x + 7
Divide by -5
y = 0.8 x -1.4
Compare this equation with y=mx+b
slope m = 0.8 0.8
The slope of a line parallel to the above line will be the same
The slope of the required line will be 0.8 => 4/5
m= 4/5 ,point ( -5 , 2 )
Find b by plugging the values of m & the point in
y=mx+b
2 = -4.00 + b
b= 6
m= 4/5
Plug value of the slope and b in y = mx +b
The required equation is y = 4/ 5 x + 6
2.Write an equation of the line containing the given point and perpendicular to the given line.
(4,8); 9x+y=8
1 y = -9 x + 8
Divide by 1
y = -9 x + 8
Compare this equation with y=mx+b
slope m = -9.00
The slope of a line perpendicular to the above line will be the negative reciprocal
m1*m2=-1
The slope of the required line will be 1/9 0.11 =
m= 1/9 ,point ( 4 , 8 )
Find b by plugging the values of m & the point in
y=mx+b
8 = 0.44 + b
b= 68/9
m= 1/9
The required equation is y= (1/9)x+68/9
m.ananth@hotmail.ca
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