Câu hỏi của Vân Đóa

Question

A= 98 . 42 - { 50 . [( 18 - 2^3 ) : 2 + 3^2]}

B= -80 - [ -130 - ( 12 - 4 )^2 ] + 2008^0

C= 1024 : 2^4 + 140 : ( 38 + 2^5 ) -7^23 : 7^21

D= ( 2^17 + 15^4 ) . ( 3^19 - 2^17 ) . ( 2^4 - 4^2 )

E= 100...

Trúc Giang · Accepted Answer

$A=98.42-\left\{50.\left[\left(18-2^3\right):2+3^2\right]\right\}$

$=98.42-\left\{50.\left[\left(18-8\right):2+9\right]\right\}$

$=98.42-\left[50\left(10:2+9\right)\right]$

$=98.42-\left(50.14\right)$

$=4116-700=3416$

$B=-80-\left[-130-\left(12-4\right)^2\right]+2008^0$

$=-80-\left(-130-8^2\right)+1$

$=-80-\left(-130-64\right)+1$

$=-80+130+64+1$

$=115$

$C=1024:2^4+140:\left(38+2^5\right)-7^{23}:7^{21}$

$=1024:16+140:\left(38+32\right)-7^2$

$=64+140:70-49$

$=64+2-49=17$

$D=\left(2^{17}+15^4\right).\left(3^{19}-2^{17}\right).\left(2^4-4^2\right)$

$=\left(2^{17}+15^4\right).\left(3^{19}-2^{17}\right).\left(16-16\right)$

$=\left(2^{17}+15^4\right).\left(3^{19}-2^{17}\right).0$

$=0$

$E=100+98+96+....+4+2-97-95-....-3-1$

$=100+\left(98-97\right)+\left(96-95\right)+.....+\left(2-1\right)+\left(1-0\right)$

$=100+1+1+...+1+1$

Vì lập được 49 cặp nên sẽ có 49 số 1

$\Rightarrow E=100+1.49=100+49=149$Câu trả lời: $A=98.42-\left\{50.\left[\left(18-2^3\right):2+3^2\right]\right\}$