Question

Tìm A \(\in N\)

a) 697 : \(\frac{15.a+364}{a}=17\)

b) 92.4 - 27 = \(\frac{a+350}{a}+315\)

Answer 1

a.\(697:\frac{15.a+364}{a}=17\)

\(\Leftrightarrow\frac{15.a+364}{a}=41\)

\(\Leftrightarrow15.a+364=41.a\)

\(\Leftrightarrow15.a-41.a=-364\)

\(\Leftrightarrow a.\left(15-41\right)=-364\)

\(\Leftrightarrow a.\left(-26\right)=-364\)

\(\Leftrightarrow a=14\)

b.\(92.4-27=\frac{a+350}{a}+315\)

\(\Leftrightarrow368-27=\frac{a+350}{a}+315\)

\(\Leftrightarrow\frac{a+350}{a}+315=341\)

\(\Leftrightarrow\frac{a+350}{a}=26\)

\(\Leftrightarrow a+350=a.26\)

\(\Leftrightarrow350=a.26-a\)

\(\Leftrightarrow a.\left(26-1\right)=350\)

\(\Leftrightarrow a.25=350\)

\(\Leftrightarrow a=14\)