Answer:
14
Explanation:
with "and" you mean "+" ?
if so, then
3 + 0.75x = 10 + 0.25x
you know that it is perfectly OK to add or subtract the same number to/from both sides of the equation ?
the same for multiplication and division.
the important thing is to do always the same thing to both sides.
1. subtracting 3 from both sides
0.75x = 7 + 0.25x
2. subtracting 0.25x from both sides
0.5x = 7
3. dividing both sides by 0.5
x = 7/0.5 = 7 / 1/2 = 7 × 2/1 = 14