\(\sqrt{97,5^2-2,5^2+15^2-85^2}\)
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\(\sqrt{97,5^2-2,5^2+15^2-85^2}\)
\(=\sqrt{\left(97,5+2,5\right)\left(97,5-2,5\right)-\left(15+85\right)\left(85-15\right)}\)
\(=\sqrt{95.100-70.100}=\sqrt{25.100}\)
\(=\sqrt{25}\sqrt{100}=5.10=50\)

a, \(\frac{8^{15^{ }}.3^{16}}{4^{23^{ }}.9^8}=\frac{2^{45}.3^{16}}{2^{46}.3^{16}}=\frac{2^{45}}{2^{46}}=\frac{1}{2}\)
b, \(\sqrt{121}-4.\sqrt{9}+\sqrt{36}=11-4.3+6=11-12+6=5\)
c,
\(\frac{2^5}{5^2}+5\frac{1}{2}.\left(4,5-2,5\right)+\frac{2^3}{-4}+\left(-2016\right)^0\)
\(\frac{4}{25}+\frac{11}{2}.2+\frac{8}{-4}+1=\frac{4}{25}+11+\left(-2\right)+1=\frac{4}{25}+10\)
= \(\frac{254}{25}\)

Ta có: 2*A = 1 + 3 + 5 + 7 + ......+ 197 + 199 ={(199 - 1) : 2 + 1}*(199 + 1) : 2 = 100 * 100 = 10000
Vậy: A = 10000 : 2 = 5000

a) \(\sqrt{0,16}+\sqrt{0,04}-\sqrt{0,25}\)
= 0,4 + 0,2 - 0,5
= 0,1
b) \(\sqrt{85^2-84^2}-\sqrt{26^2-24^2}\)
= \(\sqrt{\left(85-84\right)\left(85+84\right)}\) - \(\sqrt{\left(26-24\right)\left(26+24\right)}\)
= \(\sqrt{169}\) - \(\sqrt{2.50}\)
= 13 - 10
= 3
Chúc bạn học tốt
a) Ta có: \(\sqrt{0.16}+\sqrt{0.04}-\sqrt{0.25}\)
\(=0,4+0,2-0,5\)
=0,1

a: \(=0.5\cdot10-\dfrac{1}{7}+15=20-\dfrac{1}{7}=\dfrac{139}{7}\)
b: \(=6\cdot\dfrac{-2}{3}+12\cdot\dfrac{4}{9}+18\cdot\dfrac{-8}{27}\)
\(=-4+\dfrac{16}{3}-\dfrac{16}{3}=-4\)
c: \(=\left(\dfrac{5}{2}+\dfrac{3}{8}-\dfrac{5}{8}+\dfrac{2}{3}\right):\left(\dfrac{17}{2}+\dfrac{49}{4}-\dfrac{17}{8}+\dfrac{34}{15}\right)\)
\(=\dfrac{35}{12}:\dfrac{2507}{120}=\dfrac{350}{2507}\)

2,5 X ( 12,5 +17,3) X 97,5
= 2,5 +29,8 X 97,5
= 2,5 + 74,5 X 97,5
( tự tính)
\(=12,5\cdot2,5+2,5\cdot17,5+29,8\cdot39\cdot2,5\)
\(=2,5\cdot\left(12,5+17,5+39\right)\)
\(=2,5\cdot69\)
\(=172,5\)

a: \(E=1+1=2\)
b: \(=6+3\sqrt{5}+\sqrt{6}-\sqrt{2}+\sqrt{6}-\sqrt{5}\)
\(=6+2\sqrt{6}-\sqrt{2}+2\sqrt{5}\)
d: \(=2+\sqrt{3}+2-\sqrt{3}=4\)

2:
a: x+201=351
=>x=351-201
=>x=150
b: \(8\cdot5^2-27:25\)
\(=8\cdot25-\dfrac{27}{25}\)
\(=200-1,08=198,92\)
d: \(2023-23:\left[9+2\left(2^3-0,21\right)\right]\)
\(=2023-23:\left[9+16-0,42\right]\)
\(=2023-\dfrac{23}{25-0,42}\)
\(=2023-\dfrac{1150}{1229}=\dfrac{2485117}{1229}\)
b: 2(x-21)=84
=>x-21=84/2=42
=>x=42+21=63
c: 135-4(81-x)=55
=>4(81-x)=135-55=80
=>81-x=20
=>x=61