(x-4)(x^2+4x+16)-x(x+4)(x-4)=x^3-64-x(x^2-16)=x^3-64-x^3-16x=-16x-64=-16(x+4)
При x=-1,
-16(-1+4)=-16*3=-48
D= b^2 - 4ac = 2^2 - 4 * 1 *( - 3) = 4+12=16
√D=√16=4
x1= - 2+4 / 2 = 1
x2= - 2 - 4 / 2 = - 3
Ответ:1 ; - 3 .
Cosa=-2/√6⇒sina=√1-4/6=√2/6=1/√3
ctga=cosa/sina=-2/√6 :1/√3=2√3/√6=-√2
27-10ctga=27-10*(-√2)=27+10√2
1) (b+3)(b2-b-7)=b3-b2-7b+3b2-3b-27=b3+2b2-10b-27 2) (a+4)(a2+a-2)=a3+a2-2a+4a2+4a-8=a3+5a2+2a-8 3) (3xy-4)(6+xy)=18xy-3x2y2-24-4xy=14xy-3x2y2-24
5(y-4)+(y-2)=7
5y-20+y-2=7
6y=7+20+2
6y= 29
y= 29/6