6m^2 - 13mn - 5n^2 =
= 6m^2 - 15mn + 2mn - 5n^2 =
= 3m (2m - 5n) + n (2m - 5n) =
= (2m - 5n)(3m + n)
3(х+2)=4+2х
3х+6=4+2х
3х-2х=4-6
х= -2
5(х+1)-4х=4
5х+5-4х=4
5х-4х=4-5
х= -1
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2ac*3c/4a^2=3c^2/2a. сокращаем числитель и знаменатель на: 2a.
1.64x2-1-64x2-16x+12x-3=0
-4x=4
x=-1