( 25 2) =(2)(2) -(2)(20) =23 - 42 detrerminant of ( 2) =23 - 4x (2 2) = -4 or , x2 - 4x = -4, or , x2 - 4x + 4 = 0 or , ( x - 2)2 = 0 , x - 2=0, x = 2 solution : x = 2 C ladder , wall and ground form right angled triangle with right angle at bottom of wall as shown in attached sketch, In right angled triangle , 1 = h2 + 62, h2 = 12- 62 = 132 -52 = 169 - 25 = 144, h = sqrt ( 144 ) = 12 height of wall to which ladder reaches = 12 m wall ladder, 1 = 13h h right argh 6 25m ground 13 2 - h 2 + 5 2 6 2 = 13 2 - 52 = 169- 25= 14 4 h = UTGY = 12 m . height = In