Question 1 add 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