question 1Add or subtract. 4m2 − 10m3 − 3m2 + 20m3 A: 11m5 B: m2 + 10m3 *****C: m4 + 10m6 D: 7m2 − 30m3 Question 2: 1 pts Subtract. (9a3 + 6a2 − a) − (a3 + 6a − 3)Subtract. (9a3 + 6a2 − a) − (a3 + 6a − 3) A: 8a3 − 7a B: 8a3 + 6a2 − 7a + 3 C: 9a3 − a − 3 D: 9a3 + 6a2 + 6a − 3 ***** Question 3: 1 pts Skip to question text.A company distributes its product by train and by truck. The cost of distributing by train can be modeled as −0.06x2 + 35x − 135, and the cost of distributing by truck can be modeled as −0.03x2 + 29x − 165, where x is the number of tons of product distributed. Write a polynomial that represents the difference between the cost of distributing by train and the cost of distributing by truck. A: −0.03x2 + 6x − 300 B: −0.09x2 + 6x − 300 C: −0.03x2 + 6x + 30 D: −0.03x2 + 64x − 300 *****

we have that

question 1
Add or subtract. 
4m2 − 10m3 − 3m2 + 20m3
=(4m2-3m2)+(20m3-10m3)
=m2+10m3

the answer is the option
B: m2 + 10m3

Question 2: 
Subtract. (9a3 + 6a2 − a) − (a3 + 6a − 3)
=(9a3-a3)+(6a2)+(-a-6a)+(-3)
=8a3+6a2-7a-3

the answer is the option
B: 8a3 + 6a2 − 7a + 3 

Question 3: 
A company distributes its product by train and by truck. The cost of distributing by train can be modeled as −0.06x2 + 35x − 135, and the cost of distributing by truck can be modeled as −0.03x2 + 29x − 165, where x is the number of tons of product distributed. Write a polynomial that represents the difference between the cost of distributing by train and the cost of distributing by truck. 


we have that
[the cost of distributing by train]-[the cost of distributing by truck]
=[−0.06x2 + 35x − 135]-[−0.03x2 + 29x − 165]
=(-0.06x2+0.03x2)+(35x-29x)+(-135+165)
=-0.03x2+6x+30

the answer is the option
C: −0.03x2 + 6x + 30