whats the answer of 3x - [2y - (3x + 4y)] ?

Derivative:

diff( 2*y+6*x, x )

 

Integral:

int( 2*y+6*x, x )

 

Roots:

solve( 2*y+6*x = 0, x )

Simplify the following:
3 x-(2 y-(3 x+4 y))

 

-(3 x+4 y) = -3 x-4 y:
3 x-(2 y+-3 x-4 y)

 

Grouping like terms, 2 y-3 x-4 y = (2 y-4 y)-3 x:
3 x-((2 y-4 y)-3 x)

 

2 y-4 y = -2 y:
3 x-(-2 y-3 x)

 

-(-3 x-2 y) = 3 x+2 y:
3 x+3 x+2 y

 

3 x+3 x = 6 x:
6 x+2 y

 

Factor 2 out of 6 x+2 y:
Answer: | 2 (3 x+y)