Đáp án:
$\begin{array}{l}
B1)\\
A)\\
37,5.6,5 - 7,5.3,4 - 6,6.7,5 + 3,5.37,5\\
= 37,5.\left( {6,5 + 3,5} \right) - 7,5.\left( {3,4 + 6,6} \right)\\
= 37,5.10 - 7,5.10\\
= 375 - 75\\
= 300\\
b){2002^2} - 4\\
= \left( {2002 - 2} \right)\left( {2002 + 2} \right)\\
= 2000.2004\\
= 4008000\\
B3)\\
a)x\left( {x - 2} \right) + x - 2 = 0\\
\Leftrightarrow \left( {x - 2} \right)\left( {x + 1} \right) = 0\\
\Leftrightarrow x = 2;x = - 1\\
Vậy\,x = 2;x = - 1\\
b)5x\left( {x - 3} \right) - x + 3 = 0\\
\Leftrightarrow \left( {x - 3} \right)\left( {5x - 1} \right) = 0\\
\Leftrightarrow x = 3;x = \dfrac{1}{5}\\
Vậy\,x = 3;x = \dfrac{1}{5}\\
c)8{x^3} - 50x = 0\\
\Leftrightarrow 2x\left( {4{x^2} - 25} \right) = 0\\
\Leftrightarrow 2x\left( {2x - 5} \right)\left( {2x + 5} \right) = 0\\
\Leftrightarrow x = 0;x = \dfrac{5}{2};x = - \dfrac{5}{2}\\
Vậy\,x = 0;x = \dfrac{5}{2};x = - \dfrac{5}{2}\\
d)\left( {x - 2} \right)\left( {{x^2} + 2x + 7} \right) + 2\left( {{x^2} - 4} \right) - 5\left( {x - 2} \right) = 0\\
\Leftrightarrow \left( {x - 2} \right)\left( {{x^2} + 2x + 7 + 2\left( {x + 2} \right) - 5} \right) = 0\\
\Leftrightarrow \left( {x - 2} \right)\left( {{x^2} + 2x + 7 + 2x + 4 - 5} \right) = 0\\
\Leftrightarrow \left( {x - 2} \right)\left( {{x^2} + 4x + 6} \right) = 0\\
\Leftrightarrow x = 2\\
Vậy\,x = 2\\
B2)\\
a)5{x^5}\left( {x - 2z} \right) + 5{x^5}\left( {2z - x} \right)\\
= 5{x^5}\left( {x - 2z + 2z - x} \right)\\
= 5{x^5}.0\\
= 0\\
b)15.91,5 + 150.0,85\\
= 15.91,5 + 15.8,5\\
= 15.\left( {91,5 + 8,5} \right)\\
= 15.100\\
= 1500\\
c)\dfrac{{{{43}^2} - {{11}^2}}}{{36,{5^2} - 27,{5^2}}} = \dfrac{{\left( {43 + 11} \right)\left( {43 - 11} \right)}}{{\left( {36,5 - 27,5} \right)\left( {36,5 + 27,5} \right)}}\\
= \dfrac{{54.32}}{{9.64}}\\
= \dfrac{6}{2} = 3\\
d)\dfrac{{{{97}^3} + {{83}^3}}}{{180}} - 97.83\\
= \dfrac{{\left( {97 + 83} \right).\left( {{{97}^2} - 97.83 + {{83}^2}} \right)}}{{180}} - 97.83\\
= {97^2} - 97.83 + {83^2} - 97.83\\
= {\left( {97 - 83} \right)^2}\\
= {14^2}\\
= 196
\end{array}$
