Answer:
-2x + 12
Step-by-step explanation:
If we call our other expression y, we can set up an equation tying together 3x + 5, y, and 5x - 7:
[tex](5x-7)+y=3x+5[/tex]
Solving for y by subtracting 5x - 7 from both sides will get us the expression we're looking for:
[tex]y=3x+5-(5x-7)\\y=3x+5-5x+7\\y=-2x+12[/tex]
So the other expression in the sum is -2x + 12.
