(2+3sin²a)/(5-3+3sin²a) -sin²a=(2+3sin²a)/(2+3sin²a) -sin²a=1-sin²a=cos²a
<span>27+8a</span>³<span>=
=(3+2a)*(9-6a+4a</span>²)
Х²-у² = (х-у)(х+у)
4а²-b² = (2a-b)(2a+b)
0,09a²-9b² = (0,3a-3b)(0,3a+3b)
(53-3)*9+4*6=474 53-(3*9+4*6)=2 53-(3*9)+4*6=50 <span>(53-3*9+4)*6=180</span>