Let p and q are the roots. Then, according to Vieta's theorem, p + q == 12. The second condition is p - q = 18. So, you have this system of equations p + q = 12, p - q = 18. Add the equations. You will get 2p = 12 + 18 = 30. Hence, p = 15. Then q = 12 - p = 12 - 15 = -3. Thus the roots are 15 and -3. Then, according to Vieta's theorem, = 15*(-3) = -45. Then c = 2*(-45) = -90. Answer. c = -90, and the roots are 15 and -3.
Let zeroes (roots) be
Then:=====> =====> ------ eq (i)
Also,----- Given ------ eq (ii)
------ Adding eqs (ii) & (i)
------- Substituting 15 for in eq (i)
Also,======>
--------- Cross-multiplying