Answer:
1
= -----------
6(x + 7)
Explanation:
3x - 21 x^2 - 49
----------- ÷ -------------
18x - 18 x - 1
3x - 21 x - 1
----------- × -------------
18x - 18 x^2 - 49
Factor the top left:
3x - 21 = 3(x - 7)
Factor the bottom left:
18x - 18 = 18(x - 1)
Factor the new bottom right:
x^2 - 49 = (x + 7)(x - 7)
Multiply and simplify the faction:
3(x - 7) x - 1
----------- × -----------------
18(x - 1) (x + 7)(x - 7)
1
= -------------
6(x + 7)