Giúp vs ạ!!! Gấp ạ
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1 younger
2 taller
3 the smartest
4 more exciting
5 less
6 worst
7 cleverer
8 more expensive
9 more modern
10 more skillful
11 more peaceful
12 friendly
13 more valuable
14 more suitable
15 louder
16 better than
17 more slowly
18 higher
19 farther
20 more carefully
21 more often
22 the fastest
23 worse
24 harder
a) \(x^2+2x+1=\left(x+1\right)^2\)
\(x^2-2x+1=\left(x-1\right)^2\)
\(x^2+4x+4=\left(x+2\right)^2\)
\(x^2-4x+4=\left(x-2\right)^2\)
\(x^2+6x+9=\left(x+3\right)^2\)
\(x^2-6x+9=\left(x-3\right)^2\)
\(x^2-10x+25=\left(x-5\right)^2\)
\(x^2+10x+25=\left(x+5\right)^2\)
b) \(16x^2-8x+1=\left(4x-1\right)^2\)
c) \(4x^2+12xy+9y^2=\left(2x+3y\right)^2\)
d) \(x^2+x+\dfrac{1}{4}=\left(x+\dfrac{1}{2}\right)^2\)
e) \(x^2-x+\dfrac{1}{4}=\left(x-\dfrac{1}{2}\right)^2\)
f) \(9x^2+30x+25=\left(3x+5\right)^2\)
\(\left(x^2-x-2\right)\sqrt{x-1}=0\left(đk:x\ge1\right)\)
\(\Leftrightarrow\left(x-2\right)\left(x+1\right)\sqrt{x-1}=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=1\end{matrix}\right.\) (do x+1>0)
Ý B.
Bài 2:
a: Xét ΔABD và ΔEBD có
BA=BE
\(\widehat{ABD}=\widehat{EBD}\)
BD chung
Do đó: ΔABD=ΔEBD
Suy ra: AD=ED
b: Ta có: ΔABD=ΔEBD
nên \(\widehat{BAD}=\widehat{BED}\)
mà \(\widehat{BAD}=90^0\)
nên \(\widehat{BED}=90^0\)
hay DE\(\perp\)BC
bn cần giúp bài nào?