-2x^2-x+7=0
Variable with the highest degree's (exponent) constant, -2 is a, next variable's constant, -1 is b, the constant or number without a variable, 7 is c
using substitution put the numbers into the formula
(-b±√(b^(2)-4ac))/(a^(2))
(-(-1)±√((-1)^(2)-4(-2)(7))/((-2)^(2)) simplify
(1±√(1+56))/4
1±√(57)/4 is your answer