Đáp án:
e. \(\left( {2x + 1} \right)\left( {x + 2} \right)\)
Giải thích các bước giải:
\(\begin{array}{l}
a.15{x^2} + 7x - 2 = 15{x^2} - 3x + 10x - 2\\
= 3x\left( {5x - 1} \right) + 2\left( {5x - 1} \right)\\
= \left( {5x - 1} \right)\left( {3x + 2} \right)\\
b.{a^2} - 5a - 14 = {a^2} - 7a + 2a - 14\\
= a\left( {a - 7} \right) + 2\left( {a - 7} \right)\\
= \left( {a - 7} \right)\left( {a + 2} \right)\\
c.2{m^2} + 10m + 8 = 2{m^2} + 2m + 8m + 8\\
= 2m\left( {m + 1} \right) + 8\left( {m + 1} \right)\\
= \left( {m + 1} \right)\left( {2m + 8} \right)\\
d.4{p^2} - 36p + 56 = 4{p^2} - 28p - 8p + 56\\
= 4p\left( {p - 7} \right) - 8\left( {p - 7} \right)\\
= \left( {p - 7} \right)\left( {4p - 8} \right)\\
e.2{x^2} + 5x + 2 = 2{x^2} + x + 4x + 2\\
= x\left( {2x + 1} \right) + 2\left( {2x + 1} \right)\\
= \left( {2x + 1} \right)\left( {x + 2} \right)
\end{array}\)
