1) y'=(3x+x^3)' (x-2) + (3x+x^3) (x-2)' = (3+3x^2)(2-x)+ 3x + x^3 = 6 -3x + 6x^2 - 3x^3 + 3x + x^3 = - 2x^3 + 6x^2 + 6
8 5/7 - (3,15 - 1 2/7) + 4,25 = 11,1
1) 3,15 - 1 2/7 = 3 3/20 - 1 2/7 = 3 21/140 - 1 40/140 = 2 161/140 - 1 40/140 = 1 целая 121/140
2) 8 5/7 - 1 121/140 = 8 100/140 - 1 121/140 = 7 240/140 - 1 121/140 = 6 119/140 = 6 целых 17/20 = 6,85
3) 6,85 + 4,25 = 11,1
(√(43)-1)² = 43-2√(43)+1 = 44-2√(43).
3a+b=x, 3a-b=y
x²-y²=(x-y)(x+y)=
=(3a+b-(3a-b)(3a+b+3a-b)=
=(3a+b-3a+b)(6a)=2b*6a
12ab+9a²b²-6ab+1=
=9a²b²+6ab+1=(3ab+1)²