[1], [3] => a = 49,000/2 = 24,500 => b +c = 24,500 => c = 24,500 - b;
[2] => 25*24,500 + 20b + 15c = 1,052,000 => 20b + 15c = 1,027,500;
20b + 15*(24,500 - b) = 1,027,500 => 5b = 733,500 => b = 146,700 =>
c = - 122,200;
You just need to find distance between two points
d=

d=6
You can treat x and 2x+1 just as though they are real numbers.
So f(2x+1) = 3(2x+1) - 5 = 6x + 3 - 5 = 6x - 2
In the above, I made use of something called the distributive law which says that if a,b and c are real numbers, then a(b+c) = ab + ac.
The second one is the only equivalent equation. Simply plug in each variable in each equation. And compare!