quadratic

This question has already been answered

https://web2.0calc.com/questions/help-please_52172#r3

-Vinculum

Alternative solution:

Since we know the roots are a and b, we know that $7x^2 + x - 5 = 7(x - a)(x - b)$.

Expanding the right-hand side gives $7x^2 + x - 5 = 7x^2 - 7(a + b)x + 7ab$.

Comparing the coefficients of x on both sides: $1 = -7(a + b)$.

Therefore, $a + b = -\dfrac17$.

Now, $(a - 4) + (b - 4) = (a + b) - 8$, using this gives $(a - 4) + (b - 4) = -\dfrac17 - 8 =\boxed{ -\dfrac{57}8}$.