Sagot :
[tex](5n+6)(5n-5) =5n\cdot 5n -5n\cdot 5+6\cdot 5n-6\cdot 5=\\ \\=25n^2-25n+30n-30 =25n^2+5n-30[/tex]
(5n + 6)(5n-5)
= {5n(5n-5)} + {6(5n-5)}
= 25n² - 25n + 30n - 30
= 25n² + 5n - 30
= {5n(5n-5)} + {6(5n-5)}
= 25n² - 25n + 30n - 30
= 25n² + 5n - 30