<h3>Simplifying </h3>
9x + -31 = 43
<h3>Reorder the terms:</h3>
-31 + 9x =43
<h3>Solving</h3>
-31 + 9x =43
<h3>Solving for variable 'x' .</h3><h3>Move all terms containing x to the left, </h3>
Add '31' to each side of the equation .
0 + 31 +9x = 43 + 31
<h3>Combine like terms: </h3>
-31 + 31 =0
0 + 9x = 43 +31
9x = 43 + 31
<h3>Combine like terms:</h3>
43 + 31 =74
9x = 74
<h3>Divide each side by '9'</h3>
x = 8. 222222222
<h3>Simpifying</h3>
x = 8.222222222
C. A chord because a chord is a line segment with 2 end points
A = {1, 2, 5, 6, 8}
{1} U {2, 5, 6, 8}
{2} U {1, 5, 6, 8}
{5} U {1, 2, 6, 8}
{6} U {1, 2, 5, 8}
{8} U {1, 2, 5, 6}
{1, 2} U {5, 6, 8}
{1, 5} U {2, 6, 8}
{1, 6} U {2, 5, 8}
{1, 8} U {2, 5, 6}
{1, 2, 5} U {6, 8}
{1, 2, 6} U {5, 8}
{1, 2, 8} U {5, 6}
{1, 5, 6} U {2, 8}
{1, 5, 8} U {2, 6}
{1, 6, 8} U {2, 5}
The answer is 15 distinct pairs of disjoint non-empty subsets.