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![](https://rs.olm.vn/images/avt/0.png?1311)
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 \(\widehat{sOq}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
1:
góc bZc+góc aZb=180 độ(kề bù)
=>góc bZc=180-góc aZb=180-71=109 độ
2: góc pOn+góc pOa=180 độ(kề bù)
=>góc pOa=180-47=133 độ
3: góc xBz+góc xBm=180 độ(hai góc kề bù)
=>góc xBz=180-32=148 độ
![](https://rs.olm.vn/images/avt/0.png?1311)
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: \(\sqrt{36}+\sqrt{225}=6+15=21\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Câu 1:
\(\sqrt{16}=4\)
\(\sqrt{36}=6\)
\(\sqrt{81}=9\)
\(\sqrt{144}=12\)
\(\sqrt{625}=25\)
\(\sqrt{\dfrac{4}{9}}=\dfrac{2}{3}\)
\(\sqrt{\dfrac{36}{25}}=\dfrac{6}{5}\)
\(\sqrt{\dfrac{64}{49}}=\dfrac{8}{7}\)
\(\sqrt{\dfrac{169}{400}}=\dfrac{13}{20}\)
\(\sqrt{11\dfrac{1}{9}}=\sqrt{\dfrac{100}{9}}=\dfrac{10}{3}\)
\(\sqrt{1\dfrac{11}{25}}=\sqrt{\dfrac{36}{25}}=\dfrac{6}{5}\)
\(\sqrt{1\dfrac{13}{36}}=\sqrt{\dfrac{49}{36}}=\dfrac{7}{6}\)
Câu 2:
a) \(3.\sqrt{16}-4\sqrt{\dfrac{1}{4}}\)
\(=3.4-4.\dfrac{1}{2}\)
\(=4.\left(3-\dfrac{1}{2}\right)\)
\(=4.\dfrac{5}{2}\)
\(=10\)
b) \(-5\sqrt{\dfrac{9}{16}}+4\sqrt{0,36}-6\sqrt{0,09}\)
\(=-5.\dfrac{3}{4}+4.0,6-6.0,3\)
\(=\dfrac{-15}{4}+\dfrac{12}{5}-\dfrac{9}{5}\)
\(=\dfrac{-75+48-36}{20}=\dfrac{-63}{20}\)
c) \(2.\sqrt{9}-10.\sqrt{\dfrac{1}{25}}\)
\(=2.3-10.\dfrac{1}{5}\)
\(=6-2\)
\(=4\)
d) \(-3\sqrt{\dfrac{25}{16}}+5\sqrt{0,16}-7\sqrt{0,64}\)
\(=-3.\dfrac{5}{4}+5.0,4-7.0,8\)
\(=\dfrac{-15}{4}+2-\dfrac{28}{5}\)
\(=\dfrac{-75+40-28}{20}=\dfrac{-63}{20}\)
e) \(3\sqrt{25}-27\sqrt{\dfrac{4}{81}}\)
\(=3.5-27.\dfrac{2}{9}\)
\(=15-6\)
\(=9\)
f) \(-21\sqrt{\dfrac{100}{49}}+3\sqrt{0,04}-5\sqrt{0,25}\)
\(=-21.\dfrac{10}{7}+3.0,2-5.0,5\)
\(=-30+\dfrac{3}{5}-\dfrac{5}{2}\)
\(=\dfrac{-300+6-25}{10}=\dfrac{-319}{10}\)
h) \(5\sqrt{9}-4\sqrt{\dfrac{1}{16}}+6\sqrt{25}\)
\(=5.3-4.\dfrac{1}{4}+6.5\)
\(=15-1+30\)
\(=14+30\)
\(=44\)
g) \(10\sqrt{\dfrac{9}{25}}-14\sqrt{\dfrac{36}{49}}+24\sqrt{\dfrac{81}{64}}\)
\(=10.\dfrac{3}{5}-14.\dfrac{6}{7}+24.\dfrac{9}{8}\)
\(=6-12+27\)
\(=\left(-6\right)+27=21\)
Câu 3:
a) \(\sqrt{x}=7\)
\(=>x=49\)
b) \(\sqrt{x}=12\)
\(=>x=144\)
c) \(\sqrt{x}=15\)
\(=>x=225\)
d) \(\sqrt{x}=20\)
\(=>x=400\)
e) \(4\sqrt{x}=8\)
\(\sqrt{x}=8:4\)
\(\sqrt{x}=2\)
\(=>x=4\)
f) \(6\sqrt{x}=3\)
\(\sqrt{x}=\dfrac{3}{6}=\dfrac{1}{2}\)
\(=>x=\dfrac{1}{4}\)
g) \(\sqrt{x-1}=1\)
\(x-1=1\)
\(x=1+1\)
\(=>x=2\)
h) \(\sqrt{x+1}=2\)
\(x+1=4\)
\(x=4-1\)
\(=>x=3\)
i) \(\sqrt{x}-2=7\)
\(\sqrt{x}=7+2\)
\(\sqrt{x}=9\)
\(=>x=81\)
j) \(14-\sqrt{x}=12\)
\(\sqrt{x}=14-12\)
\(\sqrt{x}=2\)
\(=>x=4\)
k) \(12-\sqrt{x-1}=2\)
\(\sqrt{x-1}=12-2\)
\(\sqrt{x-1}=10\)
\(x-1=100\)
\(x=100+1\)
\(=>x=101\)
l) \(\sqrt{x+5}+10=20\)
\(\sqrt{x+5}=20-10\)
\(\sqrt{x+5}=10\)
\(x+5=100\)
\(x=100-5\)
\(=>x=95\)
# Wendy Dang
3:
a: ĐKXĐ: x>=0
\(\sqrt{x}=7\)
=>x=7^2=49
b: ĐKXĐ: x>=0
\(\sqrt{x}=12\)
=>x=12^2=144
c: ĐKXĐ: x>=0
\(\sqrt{x}=15\)
=>x=15^2=225
d: ĐKXĐ: x>=0
\(\sqrt{x}=20\)
=>x=20^2=400
e: ĐKXĐ: x>=0
\(4\sqrt{x}=8\)
=>\(\sqrt{x}=2\)
=>x=4
f: ĐKXĐ: x>=0
\(6\cdot\sqrt{x}=3\)
=>\(\sqrt{x}=\dfrac{3}{6}=\dfrac{1}{2}\)
=>x=1/4
g: ĐKXĐ: x>=1
\(\sqrt{x-1}=1\)
=>x-1=1
=>x=2
h: ĐKXĐ: x>=-1
\(\sqrt{x+1}=2\)
=>x+1=4
=>x=3
i: ĐKXĐ: x>=0
\(\sqrt{x}-2=7\)
=>\(\sqrt{x}=9\)
=>x=81
j: ĐKXĐ: x>=0
\(14-\sqrt{x}=12\)
=>\(\sqrt{x}=14-12=2\)
=>x=4
k: ĐKXĐ: x>=1
\(12-\sqrt{x-1}=2\)
=>\(\sqrt{x-1}=10\)
=>x-1=100
=>x=101
i: ĐKXĐ: x>=-5
\(\sqrt{x+5}+10=20\)
=>\(\sqrt{x+5}=10\)
=>x+5=100
=>x=95
![](https://rs.olm.vn/images/avt/0.png?1311)
bn cần bài nào?
mk ko thể lm hết cho bn
(chỉ làm những bài khó thôi)
![](https://rs.olm.vn/images/avt/0.png?1311)
b: AB//CD
=>\(\widehat{ABC}+\widehat{BCD}=180^0\)(hai góc trong cùng phía)
=>\(\widehat{BCD}=180^0-60^0=120^0\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(\text{f(1)=}2.1^2+1=3\)
\(\text{f(-1)=}2.\left(-1\right)^2+1=3\)
\(\text{f(2)=}2.2^2+1=9\)
\(\text{f(0)=}2.0^2+1=1\)
\(\text{f(-3)=}=2.\left(-3\right)^2+1=19\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Xét tam giác ABE, có:
AB = AE ( gt )
=> Tam giác ABE cân tại A
Mà AD là tia phân giác
=> BE vuông góc với AD
b) Ta có :
-3x + 2y = 55
\(\frac{x}{4}=\frac{y}{-5}=\frac{-3x}{-12}=\frac{2y}{-10}\)
Áp dụng tính chất dãy tỉ số bằng nhau , ta có :
\(\frac{x}{4}=\frac{y}{-5}=\frac{-3x}{-12}=\frac{2y}{-10}=\frac{-3x+2y}{-12+-10}=\frac{55}{-22}=\frac{5}{-2}\)
\(\Rightarrow\hept{\begin{cases}x=\frac{5}{-2}.4=-10\\y=\frac{5}{-2}.\left(-5\right)=\frac{25}{2}\end{cases}}\)
c) Ta có :
2x + 5y = 10
\(\frac{x}{3}=\frac{y}{4}=\frac{2x}{6}=\frac{5y}{20}\)
Áp dụng tính chất dãy tỉ số bằng nhau , ta có :
\(\frac{x}{3}=\frac{y}{4}=\frac{2x}{6}=\frac{5y}{20}=\frac{2x+5y}{6+20}=\frac{5}{13}\)
\(\Rightarrow\hept{\begin{cases}x=\frac{5}{13}.3=\frac{15}{13}\\y=\frac{5}{13}.4=\frac{20}{13}\end{cases}}\)
f) Ta có :
y - 2x = 5
4x = 5y \(\Rightarrow\frac{x}{5}=\frac{y}{4}=\frac{2x}{10}\)
Áp dụn tính chất dãy tỉ số bằng nhau , ta có :
\(\frac{x}{5}=\frac{y}{4}=\frac{2x}{10}=\frac{y-2x}{4-10}=\frac{5}{6}\)
\(\Rightarrow\hept{\begin{cases}x=\frac{5}{6}.5=\frac{25}{6}\\y=\frac{5}{6}.4=\frac{10}{3}\end{cases}}\)
g) Ta có :
x + y = 60
\(\frac{x}{y}=\frac{9}{11}\Rightarrow\frac{x}{9}=\frac{y}{11}\)
Áp dụn tính chất dãy tỉ số bằng nhau , ta có :
\(\frac{x}{9}=\frac{y}{11}=\frac{x+y}{9+11}=\frac{60}{20}=3\)
\(\Rightarrow\hept{\begin{cases}x=3.9=27\\y=3.11=33\end{cases}}\)