2. 1) 3x^2 + 9x = 0
3x(x + 3) = 0
x1 = 0; x2 = -3
3. a = 35/100 = 7/20; b = -1 2/3 = -8/3
24ab + 32a - 3b - 4 = 8a*(3b + 4) - (3b + 4) = (8a - 1)(3b + 4) =
= (8*7/20 - 1)(-3*8/3 + 4) = (14/5 - 1)(-8 + 4) = -9/5*4 = -36/5
23,3*9,1 + 16,7*6,1 - 23,3*6,6 - 16,7*3,6 =
= 23,3*(9,1 - 6,6) + 16,7*(6,1 - 3,6) = 23,3*2,5 + 16,7*2,5 =
= 2,5*(23,3 + 16,7) = 2,5*50 = 25*5 = 125
4. 1) 4x - 4y + cx - cy = 4(x - y) + c(x - y) = (4 + c)(x - y)
2) 5m - 5n + (m - n)^2 = 5(m - n) + (m - n)^2 = (m - n)(5 + m - n)
3) a^7 + 6a^3 + a^4 + 6 = a^3(a^4 + 6) + (a^4 + 6) = (a^3 + 1)(a^4 + 6) =
= (a + 1)(a^2 - a + 1)(a^4 + 6)
5. 27^4 - 9^5 = (3^3)^4 - 9^5 = (3^4)^3 - 9^5 = (9^2)^3 - 9^5 = 9^6 - 9^5 =
= 9^5*(9 - 1) = 8*9^5 - делится на 8