a)
m²n+mn²-3m-3n= mn(m+n) - 3(m+n) = (m + n)(mn - 3),
б)
x³-125= (x-5)(x²+5*x+5²) = (x - 5)(x² + 5x + 25),
в)
y³+64= (y+4)(y²-4*y+4²) = (y + 4)(y² - 4y + 16),
a)
(2a+3)-4a-(3a-5)²= 2а+3-4а-9а²+30а-25 = -9а² + 28а - 22,
б)
3(x+6)-(x-6) (x+6)= 3х+18-х²+36 = -х² + 3х + 54,
в)
(m-4)(m+3)-m²= m²+3m-4m-12-m² = -m - 12,
a)
12c²-12d²= 12*(c²-d²) = 12*(c - d)(c + d),
б)
-m²+8m-16= -(m²-8m+16) = -(m - 4)²,
в)
ax³-ay³= a*(x³-y³) = a*(x - y)(x² + xy + y²),
г)
b²c⁴-c²b⁴= b²c²*(c²-b²) = b²c²*(c - b)(c + b),
y(y+7) (y-3) = y²(y-2).
у(у²-3у+7у-21) = у³-2у²,
у³ - 3у² + 7у² - 21у - у³ + 2у² = 0,
6у² - 21у = 0,
у * (6у - 21) = 0,
у1 = 0, 6у - 21 = 0,
6у = 21,
у2 = 3,5