The rational expression

will be undefined where the denominator is zero. Values of v that make the denominator zero are v=3 and v=-2.
Excluded values of v are -2 and 3.
<span>3pi is an irrational number; the other options are not.</span>
800 + 16x = 720 + 21x. Cancel out the 720 to get 80 + 16x = 21x. Subtract 16x from both sides to get 80 = 5x. Divide by 5 to get 16 = x, or x = 16. 16 hours. The charge is 800 + 16(16), = 720 + 21(16) which = 800 + 256 = 720 + 336 which = 1,056 = 1,056. Hope this helped!
I suspect this is what you mean, if let me know
2x(3)^2+x(2)^2
2(3)(9)+3(4)
54+12=66