Question

tìm n biết

(2³+2).n+3².n+20=3.5²

Các bn làm ơn làm nhanh giúp mk

Answer 1

\(\left(2^3+2\right).n+3^2.n+20=3.5^2\)

\(\left(8+2\right).n+9.n+20=3.25\)

\(10n+9n+20=75\)

\(19n=75-20\)

\(19n=55\)

\(n=55:19=\dfrac{55}{19}\)

Vậy \(n=\dfrac{55}{19}\)

Answer 2

Giải:

\(\left(2^3+2\right).n+3^2.n+20=3.5^2\)

\(\Leftrightarrow n\left(2^3+2+3^2\right)+20=3.5^2\)

\(\Leftrightarrow n\left(8+2+9\right)+20=75\)

\(\Leftrightarrow19n+20=75\)

\(\Leftrightarrow19n=75-20\)

\(\Leftrightarrow19n=55\)

\(\Leftrightarrow n=\dfrac{55}{19}\)

Vậy \(n=\dfrac{55}{19}\).

Chúc bạn học tốt!