7. Find the number of real number solutions for the equation. x2 – 18 = 0

A. cannot be determined
B. 0
C. 1
D. 2

In a two-digit number the units' digit is 7 more than the tens' digit. the number with digits reversed is three times as large as the sum of the original number and the two digits. find the number.

Many newspapers carry a certain puzzle in which the reader must unscramble letters to form words. how many ways can the letters of emdangl be arranged? identify the correct unscrambling, then determine the probability of getting that result by randomly selecting one arrangement of the given letters.

*segment an is an altitude of right ? abc with a right angle at a. if ab = 2root 5 in and nc = 1 in, find bn, an, ac.