The trick here is to realise the significance of the constants in each equation and the significance of the central term. If we call the zeroes of equation 1 X1 and X2 then the zeroes of equation 2 are 1/X1 and 1/X2. (The factors of a quadratic can be written as (x-X1)(x-X2)=x^2-(X1+X2)x+X1X2.) The product of the zeroes are the respective constants so first divide equation 1 through by a: x^2+3x/a+7/a. X1X2=7/a and 1/X1X2=2, so X1X2=1/2=7/a. Therefore a=14. Also, X1+X2=-3/a and 1/X1+1/X2=-b=(X1+X2)/X1X2=-6/a=-6/14=-3/7, because we know X1+X2=-3/a and X1X2=1/2. Therefore, b=3/7 and the expressions are 14x^2+3x+7 and x^2+3x/7+2. The two equations become 14x^2+3x+7=0 and 7x^2+3x+14=0. Both have complex zeroes.