SOLUTION: A straight line makes on the co-ordinate axes positive intercepts whose sum is 5.If the positive line passes through the point P(-3,4),find its equation.pls....help me.

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Question 551001: A straight line makes on the co-ordinate axes positive intercepts whose sum is 5.If the positive line passes through the point P(-3,4),find its equation.pls....help me.
Answer by scott8148(6628) (Show Source):
You can put this solution on YOUR website!
let the y-intercept equal (j,0)
let the x-intercept equal (k,0)
"positive intercepts whose sum is 5" ___ j + k = 5 ___ k = 5 - j

using slope-intercept, the equation of the line will be ___ y = (-j / k)x + j

y - j = (-j / k)x

substituting ___ y - j = [-j / (5 - j)]x

substituting point P ___ 4 - j = [-j / (5 - j)](-3)

(4 - j)(5 - j) = 3j ___ j^2 - 9j + 20 = 3j ___ j^2 - 12j + 20 = 0 ___ (j - 10)(j - 2) = 0

j = 10 ___ and ___ j = 2 ___ (10 is too big)

substitute back with the value of j to find k, then put the values into the slope-intercept equation

for "standard" form
___ multiplying by k ___ ky = -jx + jk
___ adding jx ___ jx + ky = jk