Đáp án C

Ta có  A = 6 3 + 5 2 2 + 5 .3 1 + 5 = 2 3 + 5 2 2 + 5 . 3 3 + 5 3 1 + 5 = 2 1 .3 2 = 18.

63 + 24 x 3 = 63 +72 = 135 chia hết cho 5.

\(A=-5,13:\left(5\dfrac{5}{28}-1\dfrac{8}{9}.1,25+1\dfrac{16}{63}\right)\)

\(=-5,13:\left(5\dfrac{5}{28}-2\dfrac{13}{36}+1\dfrac{16}{63}\right)\)

\(=5,13:\left[\left(5-2+1\right)+\left(\dfrac{5}{28}-\dfrac{13}{36}+\dfrac{16}{63}\right)\right]\)

\(=5,13:\left(4+\dfrac{1}{14}\right)\)

\(=1,26\)

`A=-5,13:(5 5/28-1 8/9 .1,25+1 16/63)`

`A=-513/100:(145/28-17/9 .5/4+79/63)`

`A=-513/100:(145/28-85/36+79/63)`

`A=-513/100:(355/126+79/63)`

`A=-513/100:57/14`

`A=-63/50`

Đáp án:

288 + 63 : 7 = 288 + 9 = 297

\(\dfrac{63^3-37^3}{26}+\dfrac{63}{37}\)

\(=100+2\cdot63\cdot37+\dfrac{63}{37}\)

\(=\dfrac{176257}{37}\)

\(\dfrac{63^3-37^3}{26}+\dfrac{63}{37}\)

\(=100+2\cdot63\cdot37+\dfrac{63}{37}\)

\(=\dfrac{176257}{37}\)

63 : 7 + 24 x 2 – ( 81 – 72)

= 63 : 7 + 24 x 2 – 9

= 9 + 24 x 2 – 9

= 9 + 48 – 9

= 48

=4,678 x (63+15+1+21)

= 4,678 x 100

= 4678