ai giúp em đc ko ạ
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a: 12h: 0 độ
10h: 60 đọ
6h: 180 độ
5h: 150 độ
b:
a: góc nhọn: góc yMz; góc tMz
b: góc vuông: góc yMt, góc xMt
c: góc tù: góc xMz
d: góc bẹt: góc xMy
\(a,x+\dfrac{1}{2}=\dfrac{3}{4}\\ x=\dfrac{3}{4}-\dfrac{1}{2}\\ x=\dfrac{1}{2}\\ b,-\dfrac{2}{3}-x=1\\x=-\dfrac{2}{3}-1\\ x=-\dfrac{5}{3}\\ d,\dfrac{1}{4}+\dfrac{3}{4}:x=\dfrac{5}{2}\\ \dfrac{3}{4}:x=\dfrac{5}{2}-\dfrac{1}{4}\\ \dfrac{3}{4}:x=\dfrac{9}{4}\\ x=\dfrac{3}{4}:\dfrac{9}{4}\\ x=\dfrac{1}{3}\\ e,\left(x+\dfrac{1}{4}\right)\cdot\dfrac{3}{4}=-\dfrac{5}{8}\\ x+\dfrac{1}{4}=-\dfrac{5}{8}:\dfrac{3}{4}\\ x+\dfrac{1}{4}=\dfrac{5}{6}\\ x=\dfrac{5}{6}-\dfrac{1}{4}\\ x=\dfrac{7}{12}\)
\(g,\dfrac{x-3}{15}=\dfrac{-2}{5}\\ 5\left(x-3\right)=-30\\ x-3=-6\\ x=-6+3\\ x=-3\\ h,\dfrac{x}{-2}=\dfrac{-8}{x}\\ x^2=16\\ x=\pm\sqrt{16}\\ x=\pm4\\ k,\dfrac{x+2}{3}=\dfrac{x-4}{5}\\ 5\left(x+2\right)=3\left(x-4\right)\\ 5x+10=3x-12\\ 5x-3x=-12-10\\ 2x=-22\\ x=-11\)
\(m,\left(2x-1\right)^2=4\\ \Rightarrow\left[{}\begin{matrix}2x-1=2\\2x-1=-2\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}2x=3\\2x=-1\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=-\dfrac{1}{2}\end{matrix}\right.\)
1 D
2 B
3 C
4 B
5 A
6 C
7 A
8 B
9 D
10 C
11 B
12 C
13 C
14 B
15 D
16 B
17 Children like the Mid-Autumn festival because they are given many toys and sweets
18 You shouldn't wear shorts when going to the pagoda
19 C => lived
20 C => because
\(a,=\left(x+4\right)^3=\left(6+4\right)^3=10^3=1000\\ b,=x^3-1+x^3-27=2x^3-28\\ =2\left(-1\right)^3-28=-2-28=-30\\ c,=\left[4x-6-4\left(3-x\right)\right]\left[4x-64++4\left(3-x\right)\right]=6\left(8x-18\right)=12\left(4x-9\right)\\ =12\left(-7\cdot4-9\right)=12\left(-37\right)=-444\)
\(b,\Leftrightarrow\left\{{}\begin{matrix}m+1=3\\m-3\ne-3\end{matrix}\right.\Leftrightarrow m=2\\ c,\text{PT giao Ox tại hoành độ 3: }\\ x=-3;y=0\Leftrightarrow\left(m+1\right)\left(-3\right)+m-3=0\\ \Leftrightarrow-2m-6=0\Leftrightarrow m=-3\)
\(2\cdot\left(-\dfrac{3}{11}:\dfrac{5}{22}\right)\cdot\left(-\dfrac{15}{3}:\dfrac{26}{3}\right)\)
\(=2\cdot\dfrac{-6}{5}\cdot\dfrac{-15}{26}\)
\(=\dfrac{18}{13}\)