Answer:
D option is correct
( At Q3 the market is wasting society's .. )
Answer:
289 messages
equation: 
graph: attached below
Step-by-step explanation:
We can write this in slope-intercept form, or
. Since x is defined as the #of text messages, and 0.05 is the cost of a text message, 0.05 will be m. 45.5 is the base price, or the y-intercept, so it will be b.
Plugging in these numbers, we get 
now we make y = 60, since that is the total amount they have

So, they can send 290 messages for 60, but they need the bill under 60, so 1 text message less will be 289, and that's enough.
Answer:
80 × 30 = 2,400
Step-by-step explanation:
We can easily round 79 up to 80 and round 31 down to 30. This would make our expression 80 × 30, which is much easier to compute. We just take 8 × 3 (which is 24) and add two zeros onto the end of the number. This yields us an answer of 2,400 which is very close to the actual multiplication of 79 × 31 which is 2,449 (only 49 more than our estimation).
Answer: 12
Step-by-step explanation: