For the first question, multiply the first equation by -3 and then add it to the second equation:

-3(1/x + 3/y = 3/4)

+ 3/x - 2/y = 5/12

-3/x - 9/y = -9/4

+3/x - 2/y = 5/12 Find a commondenominator for the right hand sides of the equations:

-3/x - 9/y = -27/12

+3/x - 2/y = 5/12 Multiplied the right hand side of the top equation by 3/3, which is essentially multiplying by 1.

Now add them:

-11/y = -22/12

Cancel out the negatives and cross multiply to get:

12*11 = 22*y

132 = 22y

y = 6

Substitute this value back into this original equation:

3/x - 2/y = 5/12 to find x.

3/x - 2/6 = 5/12

3/x = 5/12 + 4/12 got a common denominator for the constants

3/x = 9/12

Cross Multiply:

3*12 = 9*x

36 = 9x

x = 4

For practice, Substitute the x and y values back into both of the original equations to show that they check out.