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Answer:
- 9x -5y = 4 . . . . standard form
- 9x -5y -4 = 0 . . . . general form
- y -1 = 9/5(x -1) . . . . . point-slope form
Step-by-step explanation:
The intercepts are ...
x-intercept = -4/-9 = 4/9
y-intercept = -4/5
Knowing these intercepts means we can put the equation in intercept form.
x/(4/9) -y/(4/5) = 1
The fractional intercepts make graphing somewhat difficult. However, we observe that the sum of the x- and y-coefficients is equal to the constant:
-9 +5 = -4
This means the point (x, y) = (1, 1) is on the graph. Knowing a point, we can write several equations using that point.
We like a positive leading coefficient (as for standard or general form), so we can multiply the given equation by -1.
9x -5y = 4 . . . . . standard form equation
Adding -4, so f(x,y) = 0, puts this in general form.
9x -5y -4 = 0
We can eliminate the constant by translating a line from the origin to the point we know:
9(x -1) -5(y -1) = 0
This can be rearranged to the traditional point-slope form ...
y -1 = 9/5(x -1)
Yet another equation can be written that tells you the slope is the same everywhere:
(y -1)/(x -1) = 9/5
These are only a few of the many possible forms of a linear equation.
