tính
a) \(\sqrt{\dfrac{3^2}{7^2}}\) b) \(\dfrac{\sqrt{3}^2+\sqrt{39}^2}{\sqrt{7}^2+\sqrt{91}^2}\) c) \(\dfrac{\sqrt{3}^2-\sqrt{39}^2}{\sqrt{7}^2-\sqrt{91}^2}\) d) \(\sqrt{\dfrac{39^2}{91^2}}\)
Trong các số sau, số nào bằng \(\dfrac{3}{7}\) ?
\(a=\dfrac{39}{91}\) \(b=\sqrt{\dfrac{3^2}{7^2}}\) \(c=\dfrac{\sqrt{3^2}+\sqrt{39^2}}{\sqrt{7^2}+\sqrt{91^2}}\) \(d=\dfrac{\sqrt{3^2}-\sqrt{39^2}}{\sqrt{7^2}-\sqrt{91^2}}\)
Các số bằng \(\dfrac{3}{7}\) là a ; b ; c ; d
tính:\(\dfrac{\sqrt{3^2+39^2}}{\sqrt{7^2}+\sqrt{91^2}}\)
\(\dfrac{\sqrt{3^2+39^2}}{\sqrt{7^2}+\sqrt{91^2}}\)
\(=\dfrac{1524}{7+91}=\dfrac{1524}{98}=\dfrac{762}{49}\)
tính:\(\dfrac{\sqrt{3^2+39^2}}{\sqrt{7^2}+\sqrt{91^2}}\)=
=\(\dfrac{3\sqrt{170}}{7+9}\)
=\(\dfrac{1\cdot\sqrt{100+70}}{7+3}\)
=
tính:
\(\dfrac{\sqrt{3^2+39^2}}{\sqrt{7^2}+\sqrt{91^2}}\)
\(\frac{\sqrt{3^2+\sqrt{39}^2}}{\sqrt{7^2}+\sqrt{91^2}}\)\(=\frac{3+39}{7+91}=\frac{42}{98}=\frac{3}{7}\)
TÍNH:
\(\dfrac{\sqrt{3^2+39^2}}{\sqrt{7^2+\sqrt{91^2}}}\)
\(\dfrac{\sqrt{3^2}+39^2}{\sqrt{7^2+91^2}}\)=\(\dfrac{\sqrt{42^2}}{\sqrt{98^2}}=\dfrac{42}{98}=\dfrac{3}{7}\)
rút gọn biểu thức:
a, \(\sqrt{\left(2,5-0,7\right)^2}\)
b, \(\dfrac{\sqrt{3^2}+\sqrt{39^2}}{\sqrt{7^2}+\sqrt{91^2}}1\)
Giải:
a) \(\sqrt{\left(2,5-0,7\right)^2}\)
\(=\left|2,5-0,7\right|\)
\(=\left|1,8\right|=1,8\)
Vậy ...
b) \(\dfrac{\sqrt{3^2}+\sqrt{39^2}}{\sqrt{7^2}+\sqrt{91^2}}\)
\(=\dfrac{3+39}{7+91}\)
\(=\dfrac{42}{98}=\dfrac{3}{7}\)
Vậy ...
rut gon bieu thuc:
a,\(\dfrac{\sqrt{3^2}+\sqrt{39^2}}{\sqrt{7^2}+\sqrt{91^2}}1\)
b, \(\sqrt{\left(2,5-0,7\right)^2}\)
a)\(\frac{\sqrt{3^2}+\sqrt{39^2}}{\sqrt{7^2}+\sqrt{91^2}}.1\)
=\(\frac{3+39}{7+91}\)
=\(\frac{42}{98}\)
=\(\frac{3}{7}\)
b)\(\sqrt{\left(2,5-0,7\right)^2}\)
=\(|2,5-0,7|\)
=2,5-0,7
=1,8
a,\(\dfrac{5^4.20^4}{25^5.4^5}\) b,\(\dfrac{\left(5^4-5^3\right)^3}{125^4}\) c,\(\sqrt{\left(2,5-0,7\right)^2}\) d,\(\dfrac{\sqrt{3^2+\sqrt{39^2}}}{\sqrt{7^2+\sqrt{91^2}}}1\)
Ai biết rút gọn biểu thức này k ạ??
Giups mình với!!! Cảm ơn nhiều ạ!!
a: \(=\dfrac{5^4\cdot5^4\cdot4^4}{5^{10}\cdot4^5}=\dfrac{1}{5^2}\cdot\dfrac{1}{4}=\dfrac{1}{100}\)
b: \(=\dfrac{\left[5^3\left(5-1\right)\right]^3}{5^{12}}=\dfrac{5^9}{5^{12}}\cdot\dfrac{4^3}{1}=\dfrac{4^3}{5^3}\)
c: \(=\sqrt{1.8^2}=1.8\)
cho biểu thức P=\(\dfrac{2\sqrt{x}}{\sqrt{x}+3}+\dfrac{\sqrt{x}+1}{\sqrt{x}-3}+\dfrac{3-11\sqrt{x}}{9-x}\) với x\(\ge\)0; x\(\ne\)9
1.tìm ĐKXĐ và rút gọn P
2.tính P khi x=7+2\(\sqrt{3}\)
3.tìm x để P<1