A=1990.32-990/1990.31+1000
A=1990.(31+1)-990/1990.31+1000
A=1990.31+1990-990/1990.31+1000
A=1990.31+1000/1990.31+1000
A=1
Trả lời:
\(a,\)\(A=\frac{1990.32-990}{1990.31+1000}\)
\(\Leftrightarrow A=\frac{\left(1000+990\right).32-990}{\left(1000+990\right).31+1000}\)
\(\Leftrightarrow A=\frac{1000.32+990.32-990}{1000.31+990.31+1000}\)
\(\Leftrightarrow A=\frac{1000.32+990.31}{1000.32+990.31}\)
\(\Leftrightarrow A=1\)
Vậy\(A=1\)
\(b,\)\(B=\frac{2008.2009+2000}{2009.2010-2018}\)
\(\Leftrightarrow B=\frac{2008.2009+2008-8}{2009.2010-2010-8}\)
\(\Leftrightarrow B=\frac{2008.\left(2009+1\right)-8}{(2009-1).2010-8}\)
\(\Leftrightarrow B=\frac{2008.2010-8}{2008.2010-8}\)
\(\Leftrightarrow B=1\)
Vậy\(B=1\)
Hok tốt!
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