The equation of the given curve is y = 7x3 + 11.

The slope of the tangent to a curve at (x0, y0) is 
Therefore, the slope of the tangent at the point where x = 2 is given by,

It is observed that the slopes of the tangents at the points where x = 2 and x = −2 are equal.
Hence, the two tangents are parallel.