a) 39601.              b) 9801.             c) 249001.            d) 89999.

a: \(123+26\cdot34+\left(-123\right)+26\cdot66\)

\(=123-123+26\cdot34+26\cdot66\)

\(=26\cdot\left(34+66\right)=26\cdot100=2600\)

b: -216-(-216+34)-20

=-216+216-34-20

=-34-20

=-54

a: \(2\cdot25\cdot9\cdot4=25\cdot4\cdot9\cdot2=18\cdot100=1800\)

b: \(35\cdot112-12\cdot35+50\)

\(=35\left(112-12\right)+50\)

=3500+50

=3550

c: \(16+\left(5^{16}:5^{14}-9^0\right)\)

\(=16+5^2-1\)

=25+15

=40

d: \(24\cdot7-\left[181-\left(13-4\right)^2\right]\)

\(=168-181+9^2\)

=81-13

=68

a)2.25.9.4

=(25.4).(9.2)

=100.18

1800

b)35.112-12.35+50

=35.(112-12)+50

=35.100+50

=3500+50

=3550

c)\(16+\left(5^{16}:5^{14}-9^0\right)\)

\(=16+\left(5^2-9^0\right)\)

\(=16+\left(25-1\right)\)

\(=16+24\)

\(=40\)

d)\(24.7-[181-\left(13-4\right)^2]\)

\(=24.7-[181-9^2]\)

\(=24.7-[181-81]\)

\(=24.7-100\)

\(=168-100\)

\(=68\)

Lời giải:
a. $=(36+76)-89-(44+56)$

$=112-89-100=12-89=-(89-12)=-77$
b. $=342-567-642+767-458$

$=(342-642)+(767-567)-458=-300+200-458=-100-458=-(100+458)=-558$

c. $=1892-892+852-300-852$

$=(1892-892)+(852-852)-300=1000+0-300=700$

d.

$=472-281-513-372+181-487$

$=(472-372)-(281-181)-(513+487)$

$=100-100-1000=-1000$

e.

$=912-1268-812+1368-100$

$=(912-812)+(1368-1268)-100=100+100-100=100$

a: \(274+351+126-151\)

\(=274+126+351-151\)

=400+200

=600

b: \(5^7:5^5\cdot3\cdot7\cdot4\)

\(=5^2\cdot21\cdot4\)

\(=21\cdot100=2100\)

c: \(164\cdot27+164\cdot73-400\)

\(=164\left(27+73\right)-400\)

=16400-400

=16000

d: \(300-2\cdot\left[\left(6^2-32\right):2^2+99\right]\)

\(=300-2\left[\dfrac{\left(36-32\right)}{4}+99\right]\)

=300-200

=100

Bài 1:

a. 

$=(x^3+2^3)-(x^3-2)=2^3+2=10$

b.

$=(x^2+10x+25)-4x(4x^2+12x+9)-(2x-1)(x^2-9)$
$=x^2+10x+25-16x^3-48x^2-36x-(2x^3-18x-x^2+9)$

$=-18x^3-46x^2-8x+16$

2.

a. 

$301^2=(300+1)^2=300^2+2.300+1=90000+600+1$

$=90601$

b.

$198^2=(200-2)^2=4(100-1)^2=4(100^2-2.100+1)$

$=4(10000-200+1)=4.9801=39204$

c.

$93.107=(100-7)(100+7)=100^2-7^2$

$=10000-49=9951$

d.

$127^2+146.127+73^2$

$=127^2+2.73.127+73^2$
$=(127+73)^2=200^2=40000$

b

D

a: \(=\dfrac{7+12-6}{13}=1\)

b: \(=\dfrac{13}{10}\cdot\dfrac{6-26}{13}=\dfrac{-20}{10}=-2\)

c: \(=\dfrac{3}{4}\cdot2-\dfrac{5}{2}\cdot\dfrac{-4}{3}=\dfrac{3}{2}+\dfrac{20}{6}=\dfrac{3}{2}+\dfrac{10}{3}=\dfrac{29}{6}\)

d: \(=\dfrac{3}{8}\cdot\dfrac{8}{5}+\dfrac{3}{5}\cdot\dfrac{2}{7}+\dfrac{3}{5}\cdot\dfrac{5}{7}=\dfrac{3}{5}+\dfrac{3}{5}=\dfrac{6}{5}\)

cảm ơn bn, mình đặt câu hỏi, bn thườg xuyên trả lời câu hỏi của mình. Thank you very much.

a, \(\left(301\right)^2=\left(300+1\right)^2=300^2+2.300.1+1^2\)

=90000+6000+1=90601

b,\(499^2=\left(500-1\right)^2=500^2-2.500.1+1^2\)

=10000-10000+1=1

a) 301² = ( 300 + 1 )² = 300² + 2.300.1 + 1² = 90601

b) 499² = ( 500 - 1 )² = 500² - 2.500.1 + 1² = 249001

c) 68.72 = ( 70 - 2). ( 70 + 2) = 70² - 4² = 4900 - 16 = 4884