2,

1.I enjoy telling a jokes

2.he is tall so he can touch the light

3.my brother is generous so he willing lends someone money

4.What he is he look like

5.the questions is easy so we can answer it

1,

1. Ba is not tall enough to play volleyball

2.Lan is intelligent enough to do the test

3.Hoa is skillful enough to make her handkerchief

4.his parents is rich enough to buy a new car

5.Phong and Thu are not tall enough to play basketball

xét KALH có :\(\Lambda KAL=\Lambda ALH=\Lambda HKA=90*\)

\(\Rightarrow\)KALH là hcn

\(\Rightarrow AL\)//KH và AK//LH

xét \(\Delta KAH\) và \(\Delta LHA\) có:

KHA = LAH (slt của ak//lh)

AH : cạnh chung

KAH=LHA(slt của al//kh)

\(\Rightarrow\Delta KAH=\Delta LHA\)

\(\Rightarrow\)AL=kH VÀ AK=LH

mà KH=DK , LH=LE

\(\Rightarrow\)AL=DK, AK=LE

\(\Rightarrow\)alkd và aelk là hbh

\(\Rightarrow\)ad//kl , ea //kl

\(\Rightarrow\)ad\(\equiv\)ea\(\Rightarrow\)a,d,e thẳng

a, \(\left|x^{ }\right|\)=2 \(\Rightarrow\)x=\(\pm2\)

TH 1: = (3.2+5)(2+7)- (2.2-5)(2-1)

=11 . 9+1

=99

TH2: =(3.-2)(-2+7)-(2.-2-5)(-2-1)

=-6.5+9.-3

=-30-27 = 57

a, = 2x(x²-4x+1)

b, = x(x²+2x²+4)

h, (a+ b+ c)²+ (a- b+ c)²- 4b²

=(a+ b+ c)²+ (a- b+c- 2b)(a- b+ c+ 2b)

=(a+b+c)²+(a-3b+c)(a+b+c)

=(a+b+c)(a+b+c+a-3b+c)

=(a+b+c)(2a-2b+2c)

=2(a+b+c)(a-b+c)

g, x⁴- 4x³+ 8x²- 16x+ 16

=(x⁴+ 8x²+16)- (4x³+16x)

=(x²+4)- 4x(x²+4)

=(x²+4)(1- 4x)

a, x³- x²- 5x+ 125

=- (x²+ 5x)+ (x³+125)

=-x(x+5)+ (x+5)(x²- 5x+ 25)

=(x+5)(-x+x²- 5x+ 25)

=(x+ 5)(x²- 6x+ 25)

b, (n+3)²- (n -1)²=(n+3- n+1)(n+3+ n- 1)

=4(2n+2)

=8n+ 8\(⋮8\)

a, 5^6 -10^4=5^2. 5^4 -5^4. 2^4

=5^4(5^2 -2^4)

=5^4. 9 \(⋮\) 9