Answer:
C. 4.2a + 0.8
Step-by-step explanation:
Given:
The two binomials given for addition are:
and 
Now, adding both the binomials, we get:

Distributing the positive sign inside the second binomial, we get:

Now, combining like terms using the commutative property of addition, we get:

Simplifying the above expression, we get:

Therefore, the resulting addition of the given binomials is 
Hence, option C is the correct answer.
(16y6)3 - (10z2)3 I think is the right answer
Description: They didn't distribute the 3 to both x and 5, so they just had 3x+5.
actual problem:
3(x+5)=3x+15
3x+15=3x+15
subtract 3x from both sides and end up with
15=15
Correct Answer: 15=15
It would be 32-4x=12
32-4(5)=12
32-20=12
12=12
First thing to do is to illustrate the problem, Since it was mentioned that work was along the way to training, the order is shown in the picture. Mary's home and workplace are nearer compared to her training center. It is also mentioned that the distance between work and home, denoted as x, is 2/3 of the total distance from home to training. The total distance is (x + 2.5). Thus,
x = 2/3(x+2.5)
x = 2/3 x + 5/3
1/3 x = 5/3
x = 5 km
Thus, the distance from home to work is 5 km. This means that Mary has to walk this distance twice to return home to get her shoes. Then, she will travel again the total distance of 5+2.5 = 7.5 km to get to her training center. So,
Total distance = 2(5km) + 7.5 km
Total distance = 17.5 km