9514 1404 393
Answer:
(x, y) = (326, 457)
Explanation:
Use the first equation to make an expression for y that can be substituted into the second.
y = 783 -x
10x +7(783 -x) = 6459
3x = 978 . . . . . . . . . . . . subtract 7(783) = 5481
x = 326 . . . . . . . . . . . . . divide by 3
y = 783 -326 = 457
The solution is (x, y) = (326, 457).