<span>a</span>³-+b³=(a-+b)(a²+-ab+b²)
<span>a</span>²-b²=(a-b)(a+b)<span>
1)(x-2)(x^2+2x+4)-(1+x)(x^2-x+1) = x</span>³-2³ - (x³+1³)=x³-8-x³-1=-9<span>
2)(x-3)(x^2+3x+9)-x(x+1)(x-1)= x</span>³-3³ -x(x²-1)= x³-27 -x³ + x =x-27
Sin(Π/2+L)=cosL………… 2) ctg(360°-L)=-ctgL...... 3) sin(2Π+L)=sinL..... 4) tg(3Π/2-L)=ctgL.... 5) sin(270°-L)=-cosL