Respuesta :

first divide
140 by 560
[tex]a - {a}^{2} = { a}^{ - 1} [/tex]
[tex] {b}^{2} - b = b[/tex]
[tex] \frac{1 {a}^{ - 1} }{4b} [/tex]
[tex] \frac{1}{4ab} [/tex]