Ответ равен 8a^2, так как 4*2=8, а а*а=а^2
6^(2log₆ 5) = 6^(log₆ 5²)= 5² = 25
если (6^(2log₆ 5))² = (6^(log₆ 5²))²= (5²)² = 25² = 625
log(a) b^k = k* log(a) b
a^(log(a) b)= b
cos3x*cosx = cos2x
1/2*[cos(3x-x) + cos(3x + x)] = cos2x
cos2x - cos4x = 2 cos2x
cos4x - cos2x = 0
2*[sin(4x + 2x)/2 * sin(2x - 4x)/2] = 0
1) sin3x = 0
3x = πn, n∈Z
x = πn/3, n∈z
2) sinx = 0
x = πk, k∈Z
<span>1) 81-64x^2y^2=(9-8xy)(9+8xy)
2) (2a+7b)^2-(3а-5b)^2=(2a+7b-3a+5b)(2a+7b+3a-5b)=(12b-a)(2b+5a)
3) a^2n-1= (a^n -1)(a^n +1)
4) (1-5х)(1+5х)-(3х-1)^2= 1-25x</span>²-9x²+6x-1=6x-34x²=2x(3-17x)<span>
5) (2b+a)(a-2b)+(a+3b)^2 =a</span>²-4b²+a²+6ab+9b²=2a²+6ab+5b²<span>
6) 1/2a^2+ab+1/2b^2 =1/2(a+b)</span>²<span>
7) y^4-8y^2+16 =(y</span>²-4)²<span>
8) -c+c^7=-c(1-c^6)=-c(1-c</span>³)(1+c³)=-c(1-c)(1+c+c³)(1+c)(1-c+c³)