5x(x-2)=5 kerjakan dengan cara rumus abc

5x ( x -2) = 5
5x^2 -10x -5 = 0. (dibagi 5)
x^2 -2x - 1 = 0
a = 1 , b = -2, dan c = -1
rumus abc= { -b +/- √( b^2 -4 a.c) } / 2a
x1,2 = { - -2 +/- √(-2)^2-4.1.(-1) }/2.1
x1.x2 = { 2 +/- √4 +4 }/ 2
x1,x2 = (2 +/- √8)/2
x1,2 = (2 +/- 2√2)/2
x1 = (2+ 2√2)/2
x1 = 1 + √2
x2 = (2 -2√2)/2
x2 = 1 - √2