4/5 - 1/3 = 12/15 - 5/15 = 7/15
4/5 - 3/4 = 16/20 - 15/20 = 1/20
9/14 - 2/7 = 9/14 - 4/14 = 5/14
7/10 - 2/5 = 7/10 - 4/10 = 3/10
7/12 - 2/9 = 21/36 - 8/36 = 13/36
7/10 - 4/15 = 21/30 - 8/30 = 13/30
36*2=72 72:36=2
19*5=95 95:5=19
26*3=78 78:26=3
Х²+4х-5=0
D=16+20=36=6²
х1/2=0,5(-4±6)
х1=-5
<span>х2=1</span>