lam bai 2 xJ JSJHbjbN

Đáp án:

$\begin{array}{l}
a){\left( {5 - x} \right)^2} + {\left( {x + 5} \right)^2} - \left( {2x + 10} \right)\left( {x - 5} \right)\\
 = {\left( {x - 5} \right)^2} - 2.\left( {x + 5} \right)\left( {x - 5} \right) + {\left( {x + 5} \right)^2}\\
 = {\left( {x - 5 - x - 5} \right)^2}\\
 = {\left( { - 10} \right)^2}\\
 = 100\\
b){\left( {4x - 1} \right)^2} + \left( {x - 1} \right)\left( {x + 1} \right) - \left( {2x - 1} \right)\left( {5x - 2} \right)\\
 = 16{x^2} - 8x + 1 + {x^2} - 1 - \left( {10{x^2} - 9x + 2} \right)\\
 = 7{x^2} + x - 2\\
c){\left( {x + 2} \right)^3} + {\left( {x - 3} \right)^2} - {x^2}\left( {x + 5} \right)\\
 = {x^2} + 6{x^2} + 12x + 8 + {x^2} - 6x + 9 - {x^3} - 5{x^2}\\
 = 2{x^2} + 6x + 17\\
d){\left( {x + 2} \right)^2} - \left( {x + 3} \right)\left( {x - 3} \right) + 10\\
 = {x^2} + 4x + 4 - {x^2} + 9 + 10\\
 = 4x + 23\\
e){\left( {x + 2} \right)^3} + {\left( {2x - 1} \right)^3} - 18x - 9\left( {{x^3} - 2} \right)\\
 = {x^3} + 6{x^2} + 12x + 8 + 8{x^3} - 12{x^2} + 6x - 1\\
 - 18x - 9{x^3} + 18\\
 =  - 6{x^2} + 25\\
f){\left( {4x - 1} \right)^3} - \left( {4x - 3} \right)\left( {16{x^2} + 3} \right)\\
 = 64{x^3} - 3.16{x^2} + 3.4x - 1\\
 - \left( {64{x^3} + 12x - 48{x^2} - 9} \right)\\
 = 64{x^3} - 48{x^2} + 12x - 1\\
 - 64{x^3} - 12x + 48{x^2} + 9\\
 = 8
\end{array}$