Answer:
[tex]6.\frac{1}{6}m+\frac{1}{6}n+\frac{2}{3} \\7.\ -4.3s+0.6t-2.6\\8.\ 6a+13\\9.\ \frac{3}{7}x+1\\10.\ 8b+5c+6x+11\\11.\ 14m+4y+1\\12.\ 6b + 10\\13.\ 5x+3[/tex]
Step-by-step explanation:
[tex]6.\ \frac{1}{3}n+\frac{2}{3}-\frac{1}{6}n+\frac{1}{6}m\\\\\ \frac{2}{6}n+\frac{2}{3}-\frac{1}{6}n+\frac{1}{6}m\\\\\ \frac{2}{6}n-\frac{1}{6}n+\frac{1}{6}m+\frac{2}{3}\\\\\ \frac{1}{6}n+\frac{1}{6}m+\frac{2}{3}\\\\\ \frac{1}{6}m+\frac{1}{6}n+\frac{2}{3}[/tex]<== final answer
[tex]7.\ (-3.5t-4s+4.5)+(-7.1-0.3s+4.1t)\\\\1(-3.5t-4s+4.5)+1(-7.1-0.3s+4.1t)\\\\-3.5t-4s+4.5+-7.1-0.3s+4.1t\\\\-4s-0.3s-3.5t+4.1t+4.5+-7.1\\\\-4.3s+0.6t-2.6[/tex]<== final answer
[tex]8.\ (2a+8)+(4a+5)\\\\(2a+-)+(8+-)\\\\(2a+4a)+(8+5)\\\\6a+13[/tex]<== final answer
[tex]9.\ (\frac{2}{7}x -7)+(\frac{1}{7}x+8)\\\\1(\frac{2}{7}x -7)+1(\frac{1}{7}x+8)\\\\\frac{2}{7}x -7+\frac{1}{7}x+8\\\\\frac{2}{7}x +\frac{1}{7}x-7+8\\\\\frac{3}{7}x+1[/tex]<== final answer
[tex]10.\ (8b+7)+(6x-4)+(5c+8)\\\\1(8b+7)+1(6x-4)+1(5c+8)\\\\8b+7+6x-4+5c+8\\\\8b+5c+6x+7+-4+8\\\\8b+5c+6x+3+8\\\\8b+5c+6x+11[/tex]<== final answer
[tex]11.\ (-3y-5)+(5m+7y)+(6+9m)\\\\1(-3y-5)+1(5m+7y)+1(6+9m)\\\\-3y-5+5m+7y+6+9m\\\\5m+9m-3y+7y-5+6\\\\14m+4y+1[/tex]<== final answer
[tex]12.\ b + 5b + 10\\\\6b + 10[/tex]<== final answer
13. length= x, side = 3x +1, side= x+2
[tex]13.\ x+3x+1+x+2\\\\x+3x+x+1+2\\\\5x+3[/tex]<== final answer (the perimeter)
14. 4 + n + 7m OR 4 + 1n + 7m
a. coefficients: 1 and 7
b. constants: 4
c. She made an error in identifying the coefficients. There is an invisible one in front of "n".
Hope this helps!
