SOLUTION: 1. Please help find the point slope form of the equation of the line. slope =-2/5(15,-9) 2. What is the equation of the line in point-slope form x, intercept=- 1/2 and y - inte

Algebra ->  Coordinate-system -> SOLUTION: 1. Please help find the point slope form of the equation of the line. slope =-2/5(15,-9) 2. What is the equation of the line in point-slope form x, intercept=- 1/2 and y - inte      Log On


   

Question 940108: 1. Please help find the point slope form of the equation of the line. slope =-2/5(15,-9)
2. What is the equation of the line in point-slope form
x, intercept=- 1/2 and y - intercept =5
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
1.
What we know about the line whose equation we are trying to find out:
it goes through point (15, -9)
it has a slope of m=-%282%2F5%29
the formula for the equation, given point is
y=mx%2B%28y%5B1%5D-mx%5B1%5D%29 ...plug in given point and slope
y=-%282%2F5%29x%2B%28-9-%28-2%2F5%2915%29+
y=-%282%2F5%29x%2B%28-9-%28-2%2Fcross%285%29%29cross%2815%293%29+
y=-%282%2F5%29x%2B%28-9-%28-2%293%29+
y=-%282%2F5%29x%2B%28-9-%28-6%29%29+
y=-%282%2F5%29x%2B%28-9%2B6%29+
y=-%282%2F5%29x-3+



2. What is the equation of the line in point-slope form
x-intercept=-%281%2F2%29 => point (-%281%2F2%29,0)
and
y-intercept+=5=> point (0,5)

the "point-slope" form:
y+%96+y%5B1%5D+=+m%28x+%96+x%5B1%5D%29
y+%96+y%5B1%5D+=+m%28x+%96+x%5B1%5D%29 if point (-%281%2F2%29,0)
y+%96+0+=+m%28x+%96+%28-1%2F2%29%29
y++=+m%28x+%2B1%2F2%29..............eq.1

y+%96+y%5B1%5D+=+m%28x+%96+x%5B1%5D%29 if point (0,5)=>b=5
y+%96+5+=+m%28x+%96+0%29
y+-5+=+mx+
y=+mx%2B5+..............eq.2
since eq.1 and eq.2 have same left sides, right sides must be equal too; so, we have
m%28x+%2B1%2F2%29=mx%2B5
m%28x+%2B1%2F2%29-mx=5
m%28%28x+%2B1%2F2%29-x%29=5
m%28cross%28x%29+%2B1%2F2-cross%28x%29%29=5
m%281%2F2%29=5
m=5%2F%281%2F2%29
highlight%28m=10%29

your equation is:
y=10x%2B5