Question 507877
=(-3+Y/4)/(8+Y/28)

Change the sign of / (division) to * (Multiplication), When we do that we change the numerator and denominator of the denominator of the fraction
=(-3+Y/4)*(28/8+y)
=(-3+Y)(28)/(4)*(8+y)
=(-3+Y)(7)/(8+y)
=(-21+7y)/(8+y)