Correct answers only ! this is the last day to complete this assignment and i desperately need to finish this assignment with an 100%.

 c. 7,999,999 phone numbers

A can be any digit 2-9, then there are 8 possible numbers.

B can be any digit 0-9, then there are 10 possible numbers.

C can be any digit 0-9, then there are 10 possible numbers.

X can be any digit 0-9, then there are 10 possible numbers.

X can be any digit 0-9, then there are 10 possible numbers.

X can be any digit 0-9, then there are 10 possible numbers.

X can be any digit 0-9, then there are 10 possible numbers.

Then are possible: 8·10·10·10·10·10·10 = 8·10⁶ = 8,000,000 phone numbers

But the number 867-5309 is not used then 8,000,000 - 1 = 7,999,999 possible phone numbers.

c. 7,999,999 phone numbers

answer is the third choice:

3x^5+4x^4+x^3+2x^2-10x-7=0

step-by-step explanation:

70.30

step-by-step explanation: