The value of the missing y coordinate is -5.
The given line is :
3y + 4x = 5
We need to find the value of missing y-coordinate of this point? (5, ?). Let it is k. This point will satisfy the given equation. It means, put the value of x 5 in given equation.
So, the value of the missing y coordinate is -5.
so far i think you have the right thing going for you just remember soh cah toh
sine over hypotenuse
cosine equals adjacent
tangent over hypotenuse