-9x+2=0

x² - 9x + 2 = 0

The quadratic formula is:  x  =  [ -b ± √(b² - 4·a·c) ] / ( 2·a )

The formula must be in this order:  ax² + bx + c  =  0

Your problem is in the right order; so  a = 1;  b = -9;  and  c = 2.

Putting those values into the equation:  x  =  [ -b ± √(b² - 4·a·c) ] / ( 2·a )

                                                         x  =  [ --9 ± √( (-9)² - 4·(1)·(2) ) ] / ( 2·(1) )

                                                         x  =  [ 9 ± √( 81 - 8 ) ] / ( 2)

                                                         x  =  [ 9 ± √(72) ] / ( 2)

Breaking down √(72)  =  √36·√2  =  6√2

    x  =  [ 9 ± 6√2 ] / 2

This can be split into two parts:  [ 9 + 6√2 ] / 2     and  [ 9 - 6√2 ] / 2