Answer:
D. y=-5/3x+20
Explanation:
We have the information y=3/5x+10, the lines are perpendicular, and the new line passes through (15,-5). The slops of perpendicular lines are negative reciprocals so you need to find the negative reciprocal of 3/5, so flip it to 5/3 and multiply by -1, we get the slope of the new line as -5/3. So far we have the equation y=-5/3x+b. We are given a point on the line, (15,-5), we can plug these into the equation as x and y to solve for the y-intercept, b. You set it up as -5=-5/3(15)+b. First you multiply to get -5=-25+b, then you add 25 to both sides to isolate the variable and you get b=20. Then you can use b to complete your equation with y=-5/3x+20, or letter D.