(5+2х)(7-х)=3(х+1)(4х-3) покажите с каких действий подобные и до уравнения ? !

(5 + 2x)(7 - x) = 3(x + 1)(4x - 3)
35 - 5x + 14x - 2x² = 3(4x² - 3x + 4x - 3)
-2x² + 9x + 35 = 12x² + 3x - 9
-14x² + 6x + 44 = 0
7x² - 3x - 22 = 0
D = 9 + 28×22 = 625 = 25²
x1 = (3 + 25)/14 = 28/ 14 = 2
x2 = (3 - 25)/14 = -22/14 = -11/7