That's a lot of questions. First, they're asking for how much each person pledged. Ivan said he would give $4.25, plus $1.25 per mile. As an expression, that would be 1.25m+4.25 . Vicky said that she would give $5.75, plus $.75 per mile, which would be .75m+5.75 . The second problem asks you to add the two, so add 1.25m and .75m to get the total amount she would earn per mile, which is $2. If I got paid $2 for every mile I biked, I would bike a marathon. Then add the flat payments of $4.25 and $5.75, and you get $10. So, the final equation would be 2m+10.
The last question is asking for you to find an equivalent proportional expression. To find this, you can just dividing by the greatest common factor of the two numbers. I got 2, so the equation would be 1m+5.