На 60\% вторая шоколадка дешевле,чем первая!
a² - b² = (a - b)(a + b)
1. x⁶ - 9 = (x³ - 3)(x³ + 3)
2. 2a⁴ - a³ - 2b² + ab = 2a⁴ - 2b² -a³ + ab = 2(a⁴ - b²) - a(a² -b) = 2(a² - b)(a² + b) - a(a² - b) =
= 2(a² + b)(a² - b) - a(a² - b) = (2a² + 2b)(a² - b) - a(a² - b) = (a² - b)(2a² + 2b - a)
3. a³x² + x² - a⁵x - a²x = x²(a³ + 1) - a²x(a³ + 1) = (a³ + 1)(x² - a²x)
4. x¹⁰ - 8x = x(x⁹ - 8) =
= x(x³ - 2)(x⁶ + 2x³ + 4)
5^x/2=⁴√5/25
5^(x/2)=5^(1/4-2)
5^(x/2)/=5^(-7/4)
x/2=-7/4
x=-7/2
x=-3,5€[-4;-3)
x€B
1) (y-4)^2=y^2-8y+16;
2) (5c-1)(5c+1)=25c^2-1;
3) (7x+a)^2=49x^2+14ax+a^2;
4) (3a+2b)(3a-2b)=9a^2-4b^2.