x, y - the numbers
The sum of the two numbers is 50.
[tex]x+y=50 \\
x=50-y[/tex]
The first number is 43 less than twice the second number.
[tex]x=2y-43 \\ \\
50-y=2y-43 \\
-y-2y=-43-50 \\
-3y=-93 \\
y=31 \\ \\
x=50-y=50-31=19[/tex]
The numbers are 19 and 31.