X=-1 and y=5
As when u replace the values x will give you negative 1 and when u replace negative 1 in y=-5x you get 5
The best math that i think you should take would be calculus.
X = ones, y = fives
x + y = 19....x = 19 - y
x + 5y = 59
19 - y + 5y = 59
19 + 4y = 59
4y = 59 - 19
4y = 40
y = 40/4
y = 10 <=== there are 10 five dollar bills
x + y = 19
x + 10 = 19
x = 19 - 10
x = 9 <=== there are 9 one dollar bills
I believe It’s C but use your resources to make sure
