If <em>a</em> is fixed and <em>b</em>,<em>c</em> are unknowns then the equation <em>b</em>+<em>c</em>=10-<em>a</em> has 11-<em>a</em> solutions. They are pairs (b,c): (0,10-a), (1,9-a), (2,8-a), ... (10-a,0). As <em>a</em> runs from 0 to 10 we have total number of solutions (11-0)+(11-1)+...(11-1)=11+10+...+1=(1+11)*11/2=66.
If we plug in 0 for x, we can receive the data for the year 1982. Doing so shows us that the Rural area was 1,417.4 million acres and the total area was 1,839.4 million acres. Therefore, we can conclude that the majority of the area of the United States was rural in 1982.
add 4n and 5n, which is 9. 9n=-9, and if u divide both sides by nine, n=-1
Your answer should be C! Hope that helps
The way you can get this answer you can use the calculater
