Just rank every pair of numbers for example:
The first one is: 1,-3.
2•1-3•-3>12
2+9>12
11>12
That's Incorrect. The first pair of numbers doesn't match the inequality.
Now do the same thing to all the other pairs of numbers.
Answer:
19 Cds left.
Step-by-step explanation:
The question said he used 31 Cds, so 50 minus 31 is 19.
Answer: I can't view the model.
Step-by-step explanation:
The first one seems more reasonable
Answer:
New cars sold = 20,
Used cars sold = 25
Cars serviced = 290
Step-by-step explanation:
In a month they sold fifteen less used cars than twice the number of new cars.
Lets say 'x' number of new cars were sold, then:
The number of used car sold is:

In the same month they serviced fifty more than twelve times the number of new cars sold. So the number of cars serviced is:

Altogether they sold or serviced 335 cars, so the sum of all the cars sold and serviced should be 335:

Solving for 'x' we get:




Therefore, the number of new cars sold in that month is 20.
Number of used car sold 
Number of cars serviced 
We can also cross check by summing them up:
