a) Ta có: \(-3\sqrt{16}\cdot\sqrt{90}\)

\(=-3\cdot4\cdot3\sqrt{10}\)

\(=-36\sqrt{10}\)

b) Ta có: \(3\sqrt{\dfrac{4}{3}}-3\sqrt{48}+5\sqrt{75}\)

\(=3\cdot\dfrac{2}{\sqrt{3}}-3\cdot4\sqrt{3}+5\cdot5\sqrt{3}\)

\(=2\sqrt{3}-12\sqrt{3}+25\sqrt{3}\)

\(=15\sqrt{3}\)

c) Ta có: \(4\sqrt[3]{27}-\sqrt[3]{64}-2\sqrt[3]{8}\)

\(=4\cdot3-4-2\cdot2\)

\(=12-4-4=4\)

\(A=2\sqrt{2}+3\sqrt{2}-4\sqrt{2}=\sqrt{2}\)

B=6+18-8=16

\(A=2\sqrt{2}+3\sqrt{2}-4\sqrt{2}=\sqrt{2}\\ B=2\cdot3+3\cdot6-8=6+18-8=16\)

a =2 \(\sqrt{2}\) + 3\(\sqrt{2}\)- 4\(\sqrt{2}\)

=\(\sqrt{2}\)

\(\sqrt{64}+3.\sqrt{\left(\frac{1}{2}\right)^0}-\frac{\sqrt{16}}{4}+\left(\sqrt{\left(-4\right)^2:\frac{1}{2}}\right).8\)

= \(8+3.1-\frac{4}{4}+\left(\sqrt{16:\frac{1}{2}}\right).8\) 

=\(8+3-1+\left(\sqrt{16.2}\right).8\)

=\(8+3-1+\left(\sqrt{32}\right).8\)

=\(11-1+\left(\sqrt{32}\right).8\)

= \(10+5,65685424949.8\)

= \(10+45,2548339959\)

=\(55,2548339959\)

Mình ko biết là có đúng không í

vì mình thấy đề bài có gì sai ý!!!

\(\sqrt{64}+3\sqrt{\left(\frac{1}{2}\right)^0}-\frac{\sqrt{16}}{4}+\left(\sqrt{\left(-4\right)^2}:\frac{1}{2}\right).8\)

\(=\sqrt{8^2}+3\sqrt{1}-\frac{\sqrt{4^2}}{4}+\left(\sqrt{16}:\frac{1}{2}\right).8\)

\(=8+3-\frac{4}{4}+\left(\sqrt{4^2}:\frac{1}{2}\right).8\)

\(=11-1+\left(4.2\right).8\)

\(=10+8.8=10+64=74\)

cái này bấm máy tính casio hoặc deli.... là ra ngay hoi !!!

\(\sqrt{8}+3.\sqrt{\left(\frac{1}{2}\right)^0}-\frac{\sqrt{16}}{4}+\left(\sqrt{\left(-4\right)^2}:\frac{1}{2}\right).8\)

\(=8+3-\frac{4}{4}+\left(4:\frac{1}{2}\right).8\)

\(=10+8.8\)

\(=74\)

a, \(=2\sqrt{7}-8+15\sqrt{7}-12=17\sqrt{7}-20\)

b, \(=2\sqrt{2}-10\sqrt{2}+4\sqrt{2}=-4\sqrt{2}\)

c, \(=\frac{3}{8}.\frac{4}{3}-2.\frac{2}{5}=\frac{1}{2}-\frac{4}{5}=-\frac{3}{10}\)

d, \(\sqrt{\left(\sqrt{3-1}\right)^2}-\sqrt{\left(\sqrt{3-2}\right)^2}=\sqrt{3-1}-\sqrt{3-2}=\sqrt{2}-\sqrt{1}=\sqrt{2}-1\)

e, \(\sqrt{2-3}\) không tồn tại

a)\(2\sqrt{\dfrac{16}{3}}-3\sqrt{\dfrac{1}{27}}-6\sqrt{\dfrac{4}{75}}\)

\(=2.\sqrt{\dfrac{4^2}{3}}-3.\sqrt{\dfrac{1}{3.3^2}}-6\sqrt{\dfrac{2^2}{3.5^2}}\)

\(=2.\dfrac{4}{\sqrt{3}}-3.\dfrac{1}{3\sqrt{3}}-6.\dfrac{2}{5\sqrt{3}}=\dfrac{8}{\sqrt{3}}-\dfrac{1}{\sqrt{3}}-\dfrac{12}{5\sqrt{3}}\)\(=\dfrac{23}{5\sqrt{3}}=\dfrac{23\sqrt{3}}{15}\)

b)\(\left(6\sqrt{\dfrac{8}{9}}-5\sqrt{\dfrac{32}{25}}+14\sqrt{\dfrac{18}{49}}\right).\sqrt{\dfrac{1}{2}}\)

\(=6\sqrt{\dfrac{8}{9}.\dfrac{1}{2}}-5\sqrt{\dfrac{32}{25}.\dfrac{1}{2}}+14\sqrt{\dfrac{18}{49}.\dfrac{1}{2}}\)

\(=6\sqrt{\dfrac{4}{9}}-5\sqrt{\dfrac{16}{25}}+14\sqrt{\dfrac{9}{49}}\)\(=6.\dfrac{2}{3}-5.\dfrac{4}{5}+14.\dfrac{3}{7}=6\)

c)\(\sqrt{\left(\sqrt{2}-2\right)^2}-\sqrt{6+4\sqrt{2}}=\left|\sqrt{2}-2\right|-\sqrt{4+2.2\sqrt{2}+2}=2-\sqrt{2}-\sqrt{\left(2+\sqrt{2}\right)^2}\)

\(=2-\sqrt{2}-\left(2+\sqrt{2}\right)=-2\sqrt{2}\)

a)\(\sqrt{1}\)+\(\sqrt{9}\)+\(\sqrt{25}\)+\(\sqrt{49}\)+\(\sqrt{81}\)

=1+3+5+7+9

=25

b)=\(\dfrac{1}{2}\)+\(\dfrac{1}{3}\)+\(\dfrac{1}{6}\)+\(\dfrac{1}{4}\)

=\(\dfrac{6}{12}\)+\(\dfrac{4}{12}\)+\(\dfrac{2}{12}\)+\(\dfrac{3}{12}\)

=\(\dfrac{15}{12}\)

c) =0,2+0.3+0,4

= 0.9

d) =9-8+7

=8

j) =1,2-1,3+1.4

= (-0,1)+1,4

=1,4

g) \(\dfrac{2}{5}\)+\(\dfrac{5}{2}\)+\(\dfrac{9}{10}\)+\(\dfrac{3}{4}\)

= (\(\dfrac{4}{10}\)+\(\dfrac{15}{10}\)+\(\dfrac{9}{10}\))+\(\dfrac{3}{4}\)

= \(\dfrac{14}{5}\)+\(\dfrac{3}{4}\)

=\(\dfrac{56}{20}\)+\(\dfrac{15}{20}\)

= \(\dfrac{71}{20}\)

Nhớ tick cho mk nha~

a: \(=2\cdot\dfrac{5}{4}-3\cdot\dfrac{7}{6}+4\cdot\dfrac{9}{8}=\dfrac{5}{2}-\dfrac{7}{2}+\dfrac{9}{2}=\dfrac{7}{2}\)

b: \(=18-16\cdot\dfrac{1}{2}+\dfrac{1}{16}\cdot\dfrac{3}{4}\)

=10+3/64

=643/64

c: \(=\dfrac{2}{3}\cdot\dfrac{9}{4}-\dfrac{3}{4}\cdot\dfrac{8}{3}+\dfrac{7}{5}\cdot\dfrac{5}{14}=\dfrac{3}{2}-2+\dfrac{1}{2}=2-2=0\)

a) = \(\frac{7}{2}\)

b) = \(\frac{643}{64}\)

c) = 0

\(\Leftrightarrow\sqrt{x-4}\left(4-12\cdot\dfrac{1}{2}+2\cdot2\right)=6\)

=>x-4=9

hay x=13