Раскроем скобки с учётом знаков :0,14n-13n-0,7-3,9=-1,26*0,3-4,6=-1,26*0,3-4,6=-4,978
Просто складывай
2^ -3+8 =2^5=32
Ab/ac = b/c
10mn/15mp = 2n/3p
2a²/3ab = 2a/3b
-2xy/5x²y = -2/5xu
63a²b²/42a^6b⁴ = 9/6a⁴b²
1)21^10/21/8=21^2
2)6^15/6^13=6^2
3)20^10/20^10=1
1) sin^4α+cos²α+sin²αcos²α=sin^4α+sin²αcos²α+cos²α=sin²α(sin²α+cos²α)+cos²α=sin²α+cos²α=1;
2) sin^4α-cos^4α-sin²α+cos²α=(sin²α-cos²α)(sin²α+cos²α)-sin²α+cos²α=sin²α-cos²α-sin²α+cos²α=0;
3) cos²α/(1-sin²α)=cos²α/cos²α=1;
4) (1-2sin²α)/(2cos²α-1)=(sin²α+cos²α-2sin²α)/(2cos²α-sin²α-cos²α)=(cos²α-sin²α)/(cos²α-sin²α)=1.