Is this correct? I'm not sure!

The price of a visit to the dentist is calculated according to the formula 50+100n50+100n where nn is the number of cavities the dentist finds. on your last visit to the dentist, 22 cavities were found. what was the cost of your visit?

Arectangle plot measure 20ft. by 30ft. a 3-ft.-wide sidewalk surrounds it.find the area of the sidewalk.

Atriangle has side lengths of x, x+11, and 3x+5. what is the perimeter? a. 3x^2 + 38x + 55 b. 4x + 16 c. 5x + 16 d. 3x^3 + 38x^2 + 55x