\(a,=\sqrt{6,25-0,49}=\sqrt{5,76}=2,4\)

\(b,=\sqrt{2,5-0,49}=\sqrt{2,01}\)

\(c,\sqrt{5,76}=2,4\)

Các số không bằng 2,4 là câu b và g

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 ...

c) \(\frac{5}{8}+\frac{13}{10}-9+25=\frac{717}{40}\)

d) \(\sqrt{0,2^2}=\left|0,2\right|=0,2\)

e) \(\sqrt{\left(-0.3\right)^2}=0,3\)

a) 0,6+7=7,6

b) \(\frac{2}{3}-\frac{5}{6}=\frac{-1}{6}\)

g) \(-\sqrt{\left(-1.3\right)^2}=-1,3\)

h) \(-0,7\sqrt{\left(-0,7\right)^2}=-0,49\)

x đâu bn?

a) \(\sqrt{\left(2,5+0,7\right)^2}=\left(2,5+0,7\right)=3,2\)

b) \(\frac{\sqrt{3^2}+\sqrt{39^2}}{\sqrt{7^2}+\sqrt{91^2}}=\frac{3+39}{7+91}=\frac{42}{98}=\frac{3}{7}\)

Ko có x nha bạn

hể ,đề bài yêu cầu tìm x mà???

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: \(=\dfrac{5^4\cdot5^4\cdot4^4}{5^{10}\cdot4^5}=\dfrac{1}{5^2}\cdot\dfrac{1}{4}=\dfrac{1}{100}\)

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: \(=\sqrt{1.8^2}=1.8\)

1. Tính hợp lí

a) \(0,7+\dfrac{-7}{19}-\left(-0,3\right)\)

\(=\dfrac{7}{10}+\dfrac{-7}{19}+\dfrac{3}{10}\)

\(=\left(\dfrac{7}{10}+\dfrac{3}{10}\right)+\dfrac{-7}{19}\)

\(=1+\dfrac{-7}{19}\)

\(=\dfrac{12}{19}\)

b) \(\dfrac{5}{3}.\left(-2,5\right):\dfrac{5}{6}\)

\(=\dfrac{5}{3}.\dfrac{-5}{2}.\dfrac{6}{5}\)

\(=\left(\dfrac{5}{3}.\dfrac{6}{5}\right).\dfrac{-5}{2}\)

\(=2.\dfrac{-5}{2}\)

\(=-5\)

c) \(0,6.\dfrac{-5}{17}-\dfrac{3}{5}.\dfrac{12}{17}\)

\(=\dfrac{3}{5}.\dfrac{-5}{17}-\dfrac{3}{5}.\dfrac{12}{17}\)

\(=\dfrac{3}{5}.\left(\dfrac{-5}{17}-\dfrac{12}{17}\right)\)

\(=\dfrac{3}{5}.-1\)

\(=\dfrac{-3}{5}\)

d) \(\dfrac{7}{4}.\dfrac{5}{2}-\dfrac{7}{4}.\dfrac{3}{2}\)

\(=\dfrac{7}{4}.\left(\dfrac{5}{2}-\dfrac{3}{2}\right)\)

\(=\dfrac{7}{4}.1\)

\(=\dfrac{7}{4}\)

Chúc bạn học tốt

a) 0,7+−719−(−0,3)0,7+19−7​−(−0,3)

=710+−719+310=107​+19−7​+103​

=(710+310)+−719=(107​+103​)+19−7​

=1+−719=1+19−7​

=1219=1912​

b) 53.(−2,5):5635​.(−2,5):65​

=53.−52.65=35​.2−5​.56​

=(53.65).−52=(35​.56​).2−5​

=2.−52=2.2−5​

$=-5$

c) 0,6.−517−35.12170,6.17−5​−53​.1712​

=35.−517−35.1217=53​.17−5​−53​.1712​

=35.(−517−1217)=53​.(17−5​−1712​)

=35.−1=53​.−1

=−35=5−3​

d) 74.52−74.3247​.25​−47​.23​

=74.(52−32)=47​.(25​−23​)

=74.1=47​.1

=74=47​

mình giúp rùi đó nhớ tick mình nha