Here, f(x) = e(2x − 4x^2 − 7).
Also, f'(x) = d(2x − 4x2 − 7)/dx times e(2x − 4x^2 − 7) or (2 − 8x)e(2x − 4x^2 − 7).
The equation of the line tangent to the curve of f(x) = e(2x − 4x^2 − 7) at x = 0
is given according to the slope-intercept form or y = mx + b. Then build e(2x − 4x^2 − 7) = (2 − 8x)e(2x − 4x^2 − 7)x + b
which (for x = 0) goes to e-7 = 2e-7(0) + b.
This forces b to e-7 and the tangent line is written as y = (2e-7)x + e-7.