First, we need to figure out the slope of the line with equation y=3/5 x + 10. Since this equation is written in slope-intercept form, which means y=mx+c, and m is the slope, so the slope is 3/5.
Now we got the slope of the given equation, we can now find the slope of the line that we need to find the answer to. We can also use the y=mx+c method to find, so the slope of the line that we need to answer is -5/3. We can also use another method to check, as all perpendicular lines' slope multiplies to -1, we can check that whether -5/3 x 3/5 = -1, which is yes.
Since all y-intercept points are (0, y), so we can write another algebra equation to find y.
(-5-y) / (15-0) = -5/3
(-5-y) / 15 = -5/3
y=20
So the point of the y-intercept should be (0,20)
Therefore, the final answer in the blank should be 20.
