Simplify completely:

3(3x +1)

Simplify completely:

-(8 - x)

Simplify completely:

2x(3x - 7)

Simplify completely:

- ( 6x² - 13x + 9 )

Simplify completely: $\frac{1}{2}\ \left(\ \frac{3}{4}\ x^2\ -\frac{2}{3}x\ +12\right)$  

Simplify completely:

-6x + 4(-x - 3)

Simplify completely:

-8 (5b + 2) -7 (b - 5)

Simplify completely:

17 - 8 ( 4x - 12 )

Simplify completely:

12x ( x - 7 ) - 8 ( x - 7 )

 $\left(6\div3\right)\left[\left(25\div5\right)^2\ -\left(25\div5^2\right)\right]$  

Simplify completely: