X^2 - 4x + 3 = 0
D= b^2 - 4ac = ( - 4) ^2 - 4*1*3 =16 - 12 = 4
√D=2
x1=4+2 / 2 = 3
x2 = 4 -2 / 2 = 1
Ответ: 3; 1
B₁=0,81 q=-1/3 b₆-?
b₆=b₁*q⁵=0,81*(-1/3)⁵=(81/100)*(-1/3⁵)=-3⁴*1/(100*3⁵)=-1/(3*100)=-1/300.
Ответ: b₆=-1/300.
1/sin²=1+ctg²a
1+ctg²a-1=ctg²a
ctg²a=ctg²a
A) x²-3x+2 = x^2 -2x +1 -x +1 = (x-1)^2 -(x-1)= (x-1)(x-2)
б) x⁴+5x²+9 = (x^2)^2 +6x^2 +3^2 -x^2 = (x^2 +3)^2 -x^2 = (x^2 -x +3)(x^2 +x +3)
в) a²-3ab+2b² = a^2 -2ab +b^2 -ab +b^2 = (a-b)^2 -b(a-b) = (a-b)(a-2b)