Question

which equation to 4.8+2.2x-1.4x+2.4

Answer 1

Combine Like Terms
4.8 & 2.4 are common terms.
2.2x & -1.4x are common terms. 

4.8 + 2.4 = 7.2
2.2x - 1.4x = 0.8x

The answer is 7.2 + 0.8x or 0.8x + 7.2

Answer 2

You add 4.8 to 2.4 which equals to 7.2.Then you subtract 2.2x-1.4 which equals to 0.8 so your answer is 0.8x+7.2