Find the point on the graph of the given function at which the slope of the tangent line is the given slope.
\( f ( x ) = 7 x ^ { 2 } + 4 x - 9 ; \) slope of the tangent line \( = - 4 \)
The point at which the slope of the tangent line is \( - 4 \) is ( ).
(Simplify your answer. Type an ordered pair.)