1d
2b
3b
4b

(2x+2).(2x+2)-(3x-1).(3x+1)
=(2x+2)²- 9x²-1
=4x²+8x+4-9x²-1
=-5x²+8x+3

d) 99^20 và 9999^10
\(99^{20}=\left(99^2\right)^{10}\)=\(9801^{10}\)
=>99^20 <9999^10

c) 5^36 và 11^24
\(5^{36}=\left(5^6\right)^6=15625^6\)
\(11^{24}=\left(11^4\right)^6=14614^6\)
=>  5^36 > 11^24

b) 202^303 và 303^202
\(202^{303}=\left(202^3\right)^{100}=8242408^{100}\)
\(302^{202}=\left(302^2\right)^{100}=91204^{100}\)
\(8242408^{100}>91204^{100} \)
202^303 > 303^202

a)
\(7^{30}=\left(7^3\right)^{10}=343^{10}\)
\(3^{40}=\left(3^4\right)^{10}=81^{10}\)
mà \(343^{10}>81^{10}\)
=>\(7^{30}>3^{40}\)

\(\left(a\right)\)
\(x-\dfrac{1}{4}=\dfrac{-1}{6}\)
\(x=\dfrac{1}{12}\)
/\(x+\dfrac{1}{3}\)/=3
=>    \(x+\dfrac{1}{3}=3\)    hoặc  \(-x-\dfrac{1}{3}=3\)
=>    x=\(\dfrac{8}{3}\)    hoặc x= \(\dfrac{-10}{3}\)

a. 45.34 + 45.37 + 71.23 + 33.71
=45.(34+37)+71(23+33)
= 45.71+71.56
=71(45+56)
=71.101
=7171
b. 23.46 + 23.52 + 98.35 + 98.42
= 23.(46 + 52 )+ 98.(35 + 42)
= 23.98+ 98.77
= 98.(23+77)
=98 . 100
=9800
c. 27.34 + 27.56 + 90.20 + 26.90
= 27.(34 +56) + 90.(20 + 26)
= 27.90+ 90.46
=90.(27+46)
=90.73
=6570
d. 12.37 + 12.78 + 115.29 + 115.59
=12.(37 + 78) + 115.(29 + 59)
=12.115+115.88
=115(12+88)
=115.100
=11500

bài 2
1)
/2x-7/+\(\dfrac{1}{2}=1\dfrac{1}{2}\)
/2x-7/+\(\dfrac{1}{2}=\dfrac{3}{2}\)
/2x-7/=1
=>   2x-7=1   hoặc   -2x+7 =1
       2x=8       hoặc   -2x=-6
       x=4         hoặc     x=3