a) \(3.5^2-16:2^3.2\)

\(=3.25-16:8.2\)

\(=75-2.2\)

\(=75-4\)

\(=71\)

b) \(168+\left\{\left[2\left(2^4+3^2\right)-256^0\right]:7^2\right\}\)

\(=168+\left\{\left[2\left(16+9\right)-256^0\right]:7^2\right\}\)

\(=168+\left[\left(2.25-256^0\right):7^2\right]\)

\(=168+\left[\left(50-1\right):7^2\right]\)

\(=168+\left(49:7^2\right)\)

\(=168+\left(49:49\right)\)

\(=168+1\)

\(=169\)

c) \(9^{20}:9^{18}-\left(4^2-7\right)^2+8.5^2+5600:\left(3^3+1^8\right)\)

\(=9^{20}:9^{18}-\left(16-7\right)^2+8.5^2+5600:\left(27+1\right)\)

\(=9^{20}:9^{18}-9^2+8.5^2+5600:28\)

\(=9^{20-18}-9^2+8.25+5600:28\)

\(=9^2-9^2+200+200\)

\(=81-81+200+200\)

\(=200+200\)

\(=400\)

hình như bằng 3,5

\(\left(2^3+1^5\right).1000^0+0:\left(3^2+5^0\right)+1^2+1\)

\(=\left(2^3+1\right).1+0:\left(3^2+5\right)+1:1\)

\(=2^3+1+0+1\)

\(=8+1+1\)

\(=10\)

1)

Ta có: \(\dfrac{a}{2}=\dfrac{b}{3};\dfrac{a}{3}=\dfrac{c}{4}\Leftrightarrow\dfrac{a}{6}=\dfrac{b}{9};\dfrac{a}{6}=\dfrac{c}{8}\Rightarrow\dfrac{a}{6}=\dfrac{b}{9}=\dfrac{c}{8}\)và \(a-b-c=22\)

Áp dụng tính chất dãy tỉ số bằng nhau ta có:

\(\dfrac{a}{6}=\dfrac{b}{9}=\dfrac{c}{8}=\dfrac{a-b-c}{6-9-8}=\dfrac{22}{-11}=-2\)

\(\dfrac{a}{6}=-2\Rightarrow a=-2.6=-12\)

\(\dfrac{b}{9}=-2\Rightarrow b=-2.9=-18\)

\(\dfrac{c}{8}=-2\Rightarrow c=-2.8=-16\)

Vậy \(a=-12\) ; \(b=-18\) ; \(c=-16\)

a) \(\left(2^3+1^5\right).1000^0+0:\left(3^2+5^0\right)+1^2:1\)

\(=2^3+1+0+1\)

\(=10\)

1)

a) \(x+10⋮5\)

\(\Rightarrow x+10\in U\left(5\right)=\left\{1;5\right\}\)

+)\(x+10=5\Rightarrow x=-5\)

+)\(x+10=1\Rightarrow x=-9\)

Vậy x=-5 ; x=-9

b) \(x-18⋮6\)

\(\Rightarrow x-18\in U\left(6\right)=\left\{1;2;3;6\right\}\)

+)\(x-18=1\Rightarrow x=19\)

+)\(x-18=2\Rightarrow x=20\)

+)\(x-18=3\Rightarrow x=21\)

+)\(x-18=6\Rightarrow x=24\)

Vậy x=19 ; x=20 ; x=21 ; x=24

a=2 và b=2

\(\dfrac{3}{5}x=\dfrac{2}{3}y\Rightarrow\dfrac{x}{\dfrac{2}{3}}=\dfrac{y}{\dfrac{3}{5}}\) và \(x^2-y^2=38\)

Áp dụng tính chất dãy tỉ số bằng nhau:

\(\dfrac{x}{\dfrac{2}{3}}=\dfrac{y}{\dfrac{3}{5}}=\dfrac{x^2}{\dfrac{4}{6}}=\dfrac{y^2}{\dfrac{6}{10}}=\dfrac{x^2+y^2}{\dfrac{4}{6}+\dfrac{6}{10}}=\dfrac{38}{\dfrac{19}{15}}=30\)

\(\dfrac{x}{\dfrac{2}{3}}=30\Rightarrow x=30.\dfrac{2}{3}=20\)

\(\dfrac{y}{\dfrac{3}{5}}=30\Rightarrow y=30.\dfrac{3}{5}=18\)

Vậy x=20 ; y=18

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