Question

Помогите. Срочно!!!
Разложите на множители :
а) 16-1\81у4;
б) а+а2-в-в2

Answer 1

$16- \frac{1}{81} y^{4} = 4 ^{2}-( \frac{1}{9} y^{2}) ^{2}=(4- \frac{1}{9} y^{2})(4+ \frac{1}{9} y^{2} )=[2 ^{2}-( \frac{1}{3}y) ^{2}](4+ \frac{1}{9} y^{2})$$=(2- \frac{1}{3}y)(2+ \frac{1}{3}y)(4+ \frac{1}{9} y^{2}) \\\\a+ a^{2}-b- b^{2} =( a^{2} - b^{2} )+(a-b)=(a-b)(a+b)+(a-b)=$$(a-b)(a+b+1)$