The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

Alicense plate is to consist of 44 digits followed by 55 uppercase letters. determine the number of different license plates possible if the first and second digits must be? odd, and repetition is not permitted.

Which of the following would be a reasonable estimate for the weight of a pencil? a. 1 × 10^-20 lb b. 1 × 10^20 lb c. 1 × 10^2 lb d. 1 × 10^-2 lb

Ineed with question three. i don't understand how i'm supposed to achieve 3 marks.