Question

Câu 22. (1,5 điểm) Tìm \( x \), biết:
a) \( 1,3 \cdot x - 2,3185 = 4,5065 \).

b) \(\frac{-28}{35} = \frac{16}{x}\)

c) \( 5,75 - 0,2 \cdot x = 3,75 \)

Answer 1

a:  \(1,3x-2,3185=4,5065\)

=>1,3x=4,5065+2,3185=6,825

=>x=6,825:1,3=5,25

b: \(-\dfrac{28}{35}=\dfrac{16}{x}\)

=>\(\dfrac{16}{x}=-\dfrac{4}{5}\)

=>\(x=\dfrac{16\cdot5}{-4}=\dfrac{80}{-4}=-20\)

c: 

\(5,75-0,2x=3,75\)

=>\(0,2x=5,75-3,75=2\)

=>\(x=2:0,2=10\)

Answer 2

a)\(\Leftrightarrow1,3x=4,5065+2,3185\)

\(\Leftrightarrow1,3x=6,825\)

\(\Leftrightarrow x=\dfrac{6,825}{1,3}\)\(\Leftrightarrow x=5,25\)

b)\(\Leftrightarrow x=\dfrac{16.35}{-28}\)\(\Leftrightarrow x=-20\)

c)\(\Leftrightarrow-0,2x=3,75-5,75\)

\(\Leftrightarrow-0,2x=-2\)

\(\Leftrightarrow x=\dfrac{-2}{-0,2}\)\(\Leftrightarrow x=10\)