The solution to the equation is r=9.
To solve the equation r/ r+15 = 3/8 by cross-multiplying, follow these steps:
Cross-multiply to eliminate the denominators.
Solve for the variable r.
The equation is:
r/ r+15 = 3/8
Cross-multiplying gives:
8r=3(r+15)
Distribute on the right side:
8r=3r+45
Subtract 3r from both sides:
5r=45
Divide by 5 to solve for r:
r= 45/5
r=9
So, the solution to the equation is r=9.