How many seven digit telephone numbers are possible the first digit cannot be three and the number must be a multiple of 10

900,000.

Step-by-step explanation:

If the number is a multiple of 10 it must end in zero.

The first digit can be any one of 0-9 except 3 - that is one of 9 digits.

All other positions (2nd to 6th) can be any one of 0 to 9 (10 digits).

So the number of possible telephone numbers is:

9*10*10*10*10*10

= 900,000.

practice. practice. practice.

hello from mrbilldoesmath!

answer:   x (x+6)^2, choice b

discussion:

factor x out of the equation:

x^3 + 12x^2 + 36x = x (x^2 + 12x + 36).

note that 6+6 = 12 and 6*6 = 36 so the above factors into:

x (x+6)^2

which is choice b

you,

mrb