Thực hiện phép tính
a) 5 . 2^2 – 18 : 3^2
b) 75 – ( 3.5^2-4.2^3)
c) (6^2007-6^2006) : 6^2006
d) 2.[(7- 3^3 . 3^2 ) : 2 + 99] – 100
e) (7^2005 + 7^2004) : 7^2004
f) 2^3 – 5^3 : 5^2+12 .2^2
Thực hiện phép tính a) 5 . 2^2 – 18 : 3^2 b) 75 – ( 3.5^2-4.2^3) c) (6^2007-6^2006) : 6^2006 d) 2.[(7- 3^3 . 3^2 ) : 2 + 99] – 100 e) (7^2005 + 7^20
By Caroline
Giải thích các bước giải:
a) 5 . 2² – 18 : 3²
= 5 . 4 – 18 : 9
= 20 – 2
= 18
b) 75 – ( 3 . 5² – 4 . 2³ )
= 75 – ( 3 . 25 – 4 . 8 )
= 75 – ( 3 . 25 – 32 )
= 75 – ( 75 – 32 )
= 75 – 43
= 32
c) ???
d) 2 . [( 7 – 3³ . 3² ) : 2 + 99 ] – 100
= 2 . [( 7 – $3^{5}$ ) : 2 + 99 ] – 100
= 2 . [( 7 – 243 ) : 2 + 99 ] – 100
= 2 . [ – 236 : 2 + 99 ] – 100
= 2 . [ – 118 + 99 ] – 100
= 2. – 19 – 100
= – 38 – 100
= – 138
e) ???
f) 2³ – 5³ : 5² + 12 . 2²
= 8 – 125 : 25 + 12 . 4
= 8 – 5 + 48
= 3 + 48
= 51
Hidden ninja
Đáp án:
Giải thích các bước giải:
$a,5.2^2-18:3^2$
$=5.4-18:9$
$=20-2=18$
$b,75-(3.5^2-4.2^3)$
$=75-3.25+4.8$
$=75-75+32$
$=32$
$c,(6^{2007}-6^{2006}):6^{2006}$
$=\dfrac{6^{2007}-6^{2006}}{6^{2006}}$
$=\dfrac{6^{2006}(6-1)}{6^{2006}}$
$=6-1=5$
$d,2.[(7-3^3.3^2):2+99]-100$
$=2.[(7-27.9):2+99]-100$
$=2.[-118+99]-100$
$=2.(-19)-100$
$=-38-100$
$=-138$
$e,(7^{2005}-7^{2004}):7^{2004}$
$=\dfrac{7^{2005}-7^{2004}}{7^{2004}}$
$=\dfrac{7^{2004}(5-1)}{7^{2004}}$
$=5-1=4$
$f,2^3-5^3:5^2+12.2^2$
$=8-5+12.4$
$=3+48=51$