I know this is elementary bullshit but I'm slightly retarded.

Anyway, Is there a way to find a coordinate what sits well in the graph by using ratios instead of plugging in guessed numbers?

I know I got "y=-3x-5" but the y-axis only marks intervals of 2 and the x axis only marks intervals of 5.

Since I know that the ratio on the coordinate plane is 2:5, isn't there a way to use that to figure out a coordinate that sits cleanly on the graph some way?

I got a hunch I could use LCM or something, but I can't put my finger on it.