Answer:
x = -45.5
y=57
Explanation:
.50x + .75y= 20
x + y= 11.50
Multiply the second equation by -1/2 so we can eliminate x
-.5 (x + y= 11.50)
-.5x - .5 y = -5.75
Add this equation to the first equation
-.5x - .5 y = -5.75
.50x + .75y= 20
-----------------------------
.25y = 14.25
Divide by .25
.25y/.25 = 14.25/.25
y =57
Now we still need to find x
x + y= 11.50
x + 57 = 11.5
Subtract 57 from each side
x+57-57 = 11.5-57
x = 45.5