Question

РАЗЛОЖИТЕ НА МНОЖИТЕЛИ формулой (a-b)*(a+b)

$3y^{5} - \frac{3}{25}y^{7}$

Answer 1

$3y^5-\frac{3}{25}\, y^7=3\, y^5\cdot (1-\frac{1}{25}\, y^2)=3y^5\cdot (1-\frac{1}{5}\, y)(1+\frac{1}{5}\, y)=\\\\=3y^5\cdot \frac{5-y}{5}\cdot \frac{5+y}{5}=\frac{3}{25}\, y^5\cdot (5-y)(5+y)\\\\ili\\\\3y^5-\frac{3}{25}\, y^7=\frac{3}{25}\, (25\, y^5-y^7)=\frac{3}{25}\, y^5\cdot (25-y^2)=\frac{3}{25}\, y^5\cdot (5-y)(5+y)$