3:

OE là phân giác của góc DOC

=>góc EOD=góc EOC=55 độ

góc DOC=2*góc EOC=2*55=110 độ

4:

a: góc xOz+góc yOz=180 độ(kề bù)

=>góc yOz=180-60=120 độ

b: góc mOn=góc nOz+góc mOz

=1/2(góc xOz+góc yOz)

=1/2*180=90 độ

Giải thì giải từ hình dưới r đến hình trên giúp t nha, t cảm ơn

3:

a: \(\sqrt{14^2}=14\)

b: \(\sqrt{16^2}=16\)

c: \(\sqrt{169}=13\)

d: \(\sqrt{\left(\dfrac{3}{4}\right)^2}=\dfrac{3}{4}\)

1:

a: \(\sqrt{144}=\sqrt{12^2}=12\)

b: \(\sqrt{\left(-13\right)^2}=\left|-13\right|=13\)

c: \(-\sqrt{\dfrac{16}{81}}=-\sqrt{\left(\dfrac{4}{9}\right)^2}=-\dfrac{4}{9}\)

d: \(\sqrt{36}+\sqrt{225}=6+15=21\)

Bạn cần hết ạ? Bạn tách từng bài ra các CH khác nhau, tất cả cả bài này dài lắm b.

Ê, cứu với..

Bài 2:

a) Các góc kề với góc pOq là:

\(\widehat{sOq};\widehat{nOp};\widehat{mOp}\)

b) Các góc kề bù trong hình là:

\(\widehat{mOn}\) và \(\widehat{sOn}\)

\(\widehat{mOp}\) và \(\widehat{sOp}\)

\(\widehat{mOq}\) và \(\widehat{sOq}\)

1: Các cặp góc kề bù là:

\(\widehat{mOp};\widehat{mOq}\)

\(\widehat{mOp};\widehat{nOp}\)

\(\widehat{mOq};\widehat{nOq}\)

\(\widehat{nOp};\widehat{nOq}\)

PTHH : 2Al     +     6HCl  --> 2AlCl3   +    3H2 ↑   (1)

n_AlCl3 = \(\dfrac{m}{M}=\dfrac{13,35}{27+35,5.3}=0.1\left(mol\right)\) 

Từ (1) => n_HCl   =   2n_H2  = 0.2 (mol)

=> m_HCl = n.M  =  0.2 x  36.5 = 7.3 (g)

\(PTHH:2Al+6HCl\rightarrow2AlCl_3+3H_2\\ n_{AlCl_3}=\dfrac{m}{M}=\dfrac{13,35}{133,5}=0,1\left(mol\right)\\ Theo.PTHH:n_{HCl}=3.n_{AlCl_3}=3.0,1=0,3\left(mol\right)\\ m_{HCl}=n.M=0,3.36,5=10,95\left(g\right)\)

Hình a:

\(\widehat{zAy}\) và \(\widehat{yAx}\)

Hình b:

\(\widehat{BMA}\) và \(\widehat{AMC}\)

\(\widehat{BAM}\) và \(\widehat{MAC}\)

Hình c:

\(\widehat{pOn}\) và \(\widehat{nOy}\)

\(\widehat{nOy}\) và \(\widehat{yOq}\)

\(\widehat{yOq}\) và \(\widehat{qOm}\)

\(\widehat{qOm}\) và \(\widehat{mOx}\)

\(\widehat{mOx}\) và \(\widehat{xOp}\)

\(\widehat{xOp}\) và \(\widehat{pOn}\)

\(a)\left|x+\dfrac{1}{2}\right|=3\\ x+\dfrac{1}{2}=\left\{{}\begin{matrix}3\\-3\end{matrix}\right.\\ x=\left\{{}\begin{matrix}3-\dfrac{1}{2}\\-3-\dfrac{1}{2}\end{matrix}\right.\\ x=\left\{{}\begin{matrix}\dfrac{5}{2}\\-\dfrac{7}{2}\end{matrix}\right.\)

\(b)\left|x-1,5\right|=2\\ x-1,5=\left\{{}\begin{matrix}2\\-2\end{matrix}\right.\\ x=\left\{{}\begin{matrix}2+1,5\\-2+1,5\end{matrix}\right.\\ x=\left\{{}\begin{matrix}3,5\\-0,5\end{matrix}\right.\\ c)\left|x-2,5\right|-\dfrac{3}{4}=0\\ \left|x-2,5\right|=0+\dfrac{3}{4}\\ \left|x-2,5\right|=\dfrac{3}{4}\\ x-2,5=\left\{{}\begin{matrix}\dfrac{3}{4}\\-\dfrac{3}{4}\end{matrix}\right.\\ x=\left\{{}\begin{matrix}\dfrac{3}{4}+2,5\\-\dfrac{3}{4}+2.5\end{matrix}\right.\\ x=\left\{{}\begin{matrix}3,25\\1,75\end{matrix}\right.\)

\(d)\dfrac{1}{2}-\left|\dfrac{5}{4}-2x\right|=\dfrac{1}{3}\\ \left|\dfrac{5}{4}-2x\right|=\dfrac{1}{2}-\dfrac{1}{3}\\ \left|\dfrac{5}{4}-2x\right|=\dfrac{1}{6}\\ \dfrac{5}{4}-2x=\left\{{}\begin{matrix}\dfrac{1}{6}\\-\dfrac{1}{6}\end{matrix}\right.\\ 2x=\left\{{}\begin{matrix}\dfrac{5}{4}-\dfrac{1}{6}\\\dfrac{5}{4}-\left(-\dfrac{1}{6}\right)\end{matrix}\right.\\ 2x=\left\{{}\begin{matrix}\dfrac{13}{12}\\\dfrac{17}{12}\end{matrix}\right.\\ x=\left\{{}\begin{matrix}\dfrac{13}{12}:2\\\dfrac{17}{12}:2\end{matrix}\right.\\ x=\left\{{}\begin{matrix}\dfrac{13}{24}\\\dfrac{17}{24}\end{matrix}\right.\)

\(e)\left|x-\dfrac{1}{2}\right|=4\\ x-\dfrac{1}{2}=\left\{{}\begin{matrix}4\\-4\end{matrix}\right.\\ x=\left\{{}\begin{matrix}4+\dfrac{1}{2}\\-4+\dfrac{1}{2}\end{matrix}\right.\\ x=\left\{{}\begin{matrix}\dfrac{9}{2}\\-\dfrac{7}{2}\end{matrix}\right.\\ f)\left|x+2,5\right|=3\\ x+2,5=\left\{{}\begin{matrix}3\\-3\end{matrix}\right.\\ x=\left\{{}\begin{matrix}3-2,5\\-3-2,5\end{matrix}\right.\\ x=\left\{{}\begin{matrix}0,5\\-5,5\end{matrix}\right.\)

\(g)\left|x+1,5\right|-\dfrac{1}{4}=0\\ \left|x+1,5\right|=0+\dfrac{1}{4}\\ \left|x+1,5\right|=\dfrac{1}{4}\\ x-1,5=\left\{{}\begin{matrix}\dfrac{1}{4}\\-\dfrac{1}{4}\end{matrix}\right.\\ x=\left\{{}\begin{matrix}\dfrac{1}{4}+1,5\\-\dfrac{1}{4}+1,5\end{matrix}\right.\\ x=\left\{{}\begin{matrix}1,75\\1,25\end{matrix}\right.\)

\(h)\dfrac{1}{5}-\left|\dfrac{1}{4}-3x\right|=\dfrac{1}{6}\\ \left|\dfrac{1}{4}-3x\right|=\dfrac{1}{5}-\dfrac{1}{6}\\ \left|\dfrac{1}{4}-3x\right|=\dfrac{1}{30}\\ \dfrac{1}{4}-3x=\left\{{}\begin{matrix}\dfrac{1}{30}\\-\dfrac{1}{30}\end{matrix}\right.\\ 3x=\left\{{}\begin{matrix}\dfrac{1}{4}-\dfrac{1}{30}\\\dfrac{1}{4}-\left(-\dfrac{1}{30}\right)\end{matrix}\right.\\ 3x=\left\{{}\begin{matrix}\dfrac{13}{60}\\\dfrac{17}{60}\end{matrix}\right.\\ x=\left\{{}\begin{matrix}\dfrac{13}{60}:3\\\dfrac{17}{60}:3\end{matrix}\right.\\ x=\left\{{}\begin{matrix}\dfrac{13}{180}\\\dfrac{17}{180}\end{matrix}\right.\)

\(a,\left|x\right|+\dfrac{1}{2}=3\\ \Rightarrow\left|x\right|=3-\dfrac{1}{2}\\ \Rightarrow\left|x\right|=\dfrac{5}{2}\\ \Rightarrow\left[{}\begin{matrix}x=\dfrac{5}{2}\\x=-\dfrac{5}{2}\end{matrix}\right.\)

\(b,10,23-\left|x\right|=5\\ \Rightarrow\left|x\right|=10,23-5\\ \Rightarrow\left|x\right|=5,23\\ \Rightarrow\left[{}\begin{matrix}x=5,23\\x=-5,23\end{matrix}\right.\)

\(c,2\left|x\right|-\dfrac{1}{4}=\dfrac{2}{3}\\ \Rightarrow2\left|x\right|=\dfrac{2}{3}+\dfrac{1}{4}\\ \Rightarrow2\left|x\right|=\dfrac{11}{12}\\ \Rightarrow\left|x\right|=\dfrac{11}{12}:2\\ \Rightarrow\left|x\right|=\dfrac{11}{24}\\ \Rightarrow\left[{}\begin{matrix}x=\dfrac{11}{24}\\x=-\dfrac{11}{24}\end{matrix}\right.\)

\(d,6-3\left|x\right|=\dfrac{3}{4}\\ \Rightarrow3\left|x\right|=6-\dfrac{3}{4}\\ \Rightarrow3\left|x\right|=\dfrac{21}{4}\\ \Rightarrow\left|x\right|=\dfrac{21}{4}:3\\ \Rightarrow\left|x\right|=\dfrac{7}{4}\\ \Rightarrow\left[{}\begin{matrix}x=\dfrac{7}{4}\\x=-\dfrac{7}{4}\end{matrix}\right.\)

\(a)\left|x\right|+\dfrac{1}{2}=3\\ \left|x\right|=3-\dfrac{1}{2}\\ \left|x\right|=\dfrac{5}{2}\\ x=\left\{{}\begin{matrix}\dfrac{5}{2}\\-\dfrac{5}{2}\end{matrix}\right.\\ b)10,23-\left|x\right|=5\\ \left|x\right|=10,23-5\\ \left|x\right|=5,23\\ x=\left\{{}\begin{matrix}5,23\\-5,23\end{matrix}\right.\\ c)2\left|x\right|-\dfrac{1}{4}=\dfrac{2}{3}\\ 2\left|x\right|=\dfrac{2}{3}.\dfrac{1}{4}\\ 2\left|x\right|=\dfrac{11}{12}\\ \left|x\right|=\dfrac{11}{12}:2\\ \left|x\right|=\dfrac{11}{24}\\ x=\left\{{}\begin{matrix}\dfrac{11}{24}\\-\dfrac{11}{24}\end{matrix}\right.\)

\(d)6-3\left|x\right|=\dfrac{3}{4}\\ 3\left|x\right|=6-\dfrac{3}{4}\\ 3\left|x\right|=\dfrac{21}{4}\\ \left|x\right|=\dfrac{7}{4}\\ x=\left\{{}\begin{matrix}\dfrac{7}{4}\\-\dfrac{7}{4}\end{matrix}\right.\)

a: Vì \(\widehat{tOn}=\widehat{tOx}\)

và tia Ot nằm giữa hai tia On và Ox

nên Ot là phân giác của góc nOx

b: \(\widehat{mOx}+\widehat{nOx}=180^0\)(hai góc kề bù)

=>\(\widehat{nOx}+50^0=180^0\)

=>\(\widehat{nOx}=130^0\)

Bài 4:

a: Thể tích của hình hộp là: \(25\cdot3=75\left(cm^3\right)\)

b: Độ dài cạnh của đáy là \(\sqrt{25}=5\left(cm\right)\)

Diện tích xung quanh là: \(2\left(5+5\right)\cdot3=6\cdot10=60\left(cm^2\right)\)

bài 5:

a: Thể tích bể nước mà bể chứa được tối đa là;

\(40\cdot30\cdot25=30000\left(cm^3\right)=30\left(lít\right)\)

b: Diện tích xung quanh là:

\(2\left(40+30\right)\cdot25=50\cdot70=3500\left(cm^2\right)\)

Diện tích kính dùng làm bể là:

\(3500+2\cdot40\cdot30=5900\left(cm^2\right)\)