25×(x:21,91+1,24)=109,6

25 * ( x / 21.91 + 1.24 ) = 109.6x / 21.91 + 1.24 = 10.96 / 25x / 21.91 + 1.24 = 4.384x / 21.91 = 4.384 - 1.24x / 21.91 = 3.144x = 3.144 * 21.91x = 68.88504