Đáp án:
\(\begin{array}{l}
a)70\\
b) - \dfrac{{105}}{2}\\
c)15 - 4\sqrt 7 \\
d)6 - 2\sqrt 3 \\
e)8\\
f)2
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
a)17 - \left| { - 15} \right| + \left| {{2^2}} \right| + {\left| { - 4} \right|^3}\\
= 17 - 15 + 4 + 64 = 70\\
b)3.\sqrt {\dfrac{{25}}{4}} - 40.\sqrt {\dfrac{9}{4}} \\
= 3.\dfrac{5}{2} - 40.\dfrac{3}{2} = - \dfrac{{105}}{2}\\
c)5\left| {3 - \sqrt 7 } \right| + \sqrt 7 \\
= 5\left( {3 - \sqrt 7 } \right) + \sqrt 7 \\
= 15 - 4\sqrt 7 \\
d)\left| {2 - \sqrt 3 } \right| + \left| {4 - \sqrt 3 } \right|\\
= 2 - \sqrt 3 + 4 - \sqrt 3 \\
= 6 - 2\sqrt 3 \\
e)\left| {3 + \sqrt 5 } \right| + \left| {5 - \sqrt 5 } \right|\\
= 3 + \sqrt 5 + 5 - \sqrt 5 \\
= 8\\
f)\sqrt 7 - \sqrt {7 - 2.2\sqrt 7 + 4} \\
= \sqrt 7 - \sqrt {{{\left( {\sqrt 7 - 2} \right)}^2}} \\
= \sqrt 7 - \sqrt 7 + 2 = 2
\end{array}\)
