Question

Giải các phương trình sau:

a) 1,2x - 6 =0

b)7y - 1×1/6=9

c) -1/2u + 3×1/2u +12= 2020

d) 1990- 0,5v=v

Answer 1

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Answer 2

Answer 3

a)

\(1.2x-6=0\\ \Leftrightarrow x=\frac{6}{1.2}=5\)

b)

\(7y-1\cdot\frac{1}{6}=9\\ \Leftrightarrow7y-\frac{1}{6}=9\\ \Leftrightarrow7y=9+\frac{1}{6}=\frac{55}{6}\\ \Rightarrow y=\frac{\frac{55}{6}}{7}=\frac{55}{42}\)

c)

\(-\frac{1}{2u}+3\cdot\frac{1}{2u}+12=2020\\ \Leftrightarrow-\frac{1}{2u}+\frac{3}{2u}+12-2020=0\\ \Leftrightarrow\frac{2}{2u}-2008=0\\ \Leftrightarrow\frac{1}{u}-2008=0\\ \Leftrightarrow\frac{1}{u}=2008\\ \Rightarrow u=\frac{1}{2008}\)

d)

\(1990-0.5v=v\\ \Leftrightarrow1990-0.5v-v=0\\ \Leftrightarrow1990-1.5v=0\\ \Leftrightarrow1.5v=1990\\ \Rightarrow v=\frac{3980}{3}\)