To write 310x as a fraction with a common denominator, multiply by 3y3y.
To write -415y as a fraction with a common denominator, multiply by 2x2x.
Write each expression with a common denominator of 30xy, by multiplying each by an appropriate factor of 1.
Multiply 310x and 3y3y.
Multiply 3 by 10.
Multiply 415y and 2x2x.
Multiply 2 by 15.
Reorder the factors of 30yx.
Combine the numerators over the common denominator.
Simplify the numerator.
Multiply 3 by 3.
Multiply 2 by -4.