0 votes 0 votes Digital Logic number-system + – sagar27 asked Sep 23, 2018 reopened Jul 7, 2022 by gatecse sagar27 295 views answer comment Share Follow See all 4 Comments See all 4 4 Comments reply Magma commented Sep 23, 2018 reply Follow Share X2 - (P)r X + (Q)r = 0 In gate we put the value and check which one if correct X2 - (23)5 X + (130)5 = 0 X2 - 1310 X +4010 = 0 we know that in quadratic equation Product of roots = c/a = 40 and sum of roots = -b/a = 13 And then whether LHS = RHS or not Sum of products = 13 LHS = 810 + 510 = (8+5)10 = (13)10 LHS = RHS Now , Product of roots = 40 LHS = (5)10 * (8)10 = (40)10 Hence, LHS = RHS therefore a) is the correct answer 1 votes 1 votes Mk Utkarsh commented Sep 23, 2018 reply Follow Share $\left ( 23 \right )_5 = (13)_{10}$ $\left ( 130 \right )_5 = (40)_{10}$ $x^2 - 13x + 40$ solve the equation 1 votes 1 votes Magma commented Sep 23, 2018 reply Follow Share but In gate exam if option a is not correct and option d is right..then it's very time consuming approach to solve the equation each time Mk Utkarsh 0 votes 0 votes Mk Utkarsh commented Sep 23, 2018 reply Follow Share Magma yes can take more than 3 mins :( depends on equation. 0 votes 0 votes Please log in or register to add a comment.