Ive tried to do the problem but i got confused

When generalized, slope-intercept form is: y = m x + b

We have the slope, m = -2, but we still need the y-intercept, b, to complete the equation.

But we do have a point on the line, (10,-9). And if that point is on the line, it must satisfy the equation.

So it must be true that:

(-9) = -2(10) + b [multiply]

-9 = -20 + b [add 20]

11 = b

Now we know both the slope, m = -2, and the y-intercept, b = 11;

so our equation is: y = -2x + 11