The line through (5,-7) and decreasing at a rate of 3 units of y per 5 units of x.

Is this supposed to mean 5x-3y (the latter)?

Or actually, is it supposed to be -3/5?

Per... that is divide. And they must actually mean rise over run. Change in y over change in x.

m=-3/5 and they must want me to plug it into the slope intercept form with point (5,-7).

y=3/5x-4. I think I solved it.

sign of the slope?

"decreasing" means negative slope.

No, the expression 5x-3y does not represent the line described in the given information. Allow me to explain how to find the equation of the line through the point (5,-7) and decreasing at a rate of 3 units of y per 5 units of x.

To find the equation of a line, we can use the point-slope form: y - y₁ = m(x - x₁), where (x₁, y₁) is a point on the line, and m is the slope of the line.

Given that the line is decreasing at a rate of 3 units of y per 5 units of x, we can determine the slope. The slope of a line is the change in y divided by the change in x. In this case, the change in y is -3 (decreasing by 3 units) and the change in x is 5. Therefore, the slope is -3/5.

Using the point-slope form and substituting the values we have:
y - (-7) = -3/5(x - 5)

Simplifying the equation gives us:
y + 7 = -3/5(x - 5)

This is the equation of the line through the given point (5,-7) and decreasing at a rate of 3 units of y per 5 units of x.