1. ## [SOLVED] equation

hi, i've got the question-

find the range of values of the constant c for which the line $y = 3x + c$ does not intersect the parabola with equation $y = 2x^2 + 5x - 7$

i know you have to have a discriminant thats less than 0 for this so i strted by putting the equation into one like this $2x^2 + 2x + (-7 - c)$ so then used the theory : $(2)^2 - 4(2)(-7-c)$ which came to $4 - (- 56 - 8c)$ which then became $(60 - 8c) < 0$ then i made it $- 8c < - 60$ leaving $c < 7.5$.

the answer the book gives me is $c < - 7.5$

can some explain this please? thanks

2. ah i just realised, i should have made it + 8c rather than - 8c