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a) $3^8:3^6=3^{8-6}=3^2$
$19^7:19^3=19^{7-3}=19^4$
$2^{10}:8^3=2^{10}:(2^3)^3=2^{10}:2^9=2^{10-9}=2^1$
$12^7:6^7=(12:6)^7=2^7$
$27^5:81^3=(3^3)^5:(3^4)^3=3^{15}:3^{12}=3^{15-12}=3^3$
b) $10^6:10=10^{6-1}=10^5$
$5^8:25^2=5^8:(5^2)^2=5^8:5^4=5^{8-4}=5^4$
$4^9:64^2=4^9:(4^3)^2=4^9:4^6=4^{9-6}=4^3$
$2^25:32^4=2^{25}:(2^5)^4=2^{25}:2^{20}=2^{25-20}=2^5$
$18^3:9^3=(18:9)^3=2^3$
\(\cdot3^8:3^6=3^{8-6}=3^2\)
\(\cdot19^7:19^3=19^{7-3}=19^4\)
\(\cdot2^{10}:8^3=2^{10}:\left(2^3\right)^3=2^{10}:2^9=2\)
\(\cdot12^7:6^7=\left(12:6\right)^7=2^7\)
\(\cdot27^5:81^3=\left(3^3\right)^5:\left(3^4\right)^3=3^{15}:3^{12}=3^3\)
\(\cdot10^6:10=10^{6-1}=10^5\)
\(\cdot5^8:25^2=5^8:\left(5^2\right)^2=5^8:5^4=5^4\)
\(\cdot4^9:64^2=4^9:\left(4^3\right)^2=4^9:4^6=4^3\)
\(2^{25}:32^4=2^{25}:\left(2^5\right)^4=2^{25}:2^{20}=2^5\)
\(18^3:9^3=\left(18:9\right)^3=2^3\)
a,71.2-6.(2x+5)=10^5:10^3
142-6.(2x+5)=10^2
142-6.(2x+5)=100
6.(2x+5)=142-100
6.(2x+5)=42
2x+5=42:6
2x+5=7
2x=7-5
2x=2
x=1
Vậy x=1
a)3 . 103 + 2 . 102 + 5 . 10
= 3 . 102 . 10 + 2 . 10 . 10 + 5 . 10
= 10 . ( 3 . 102 + 2 . 10 + 5 )
= 10 . ( 3 . 100 + 20 + 5 )
= 10 . ( 300 + 20 + 5 )
= 10 . 325
= 3250
a) 3 . 103 + 2 . 102 + 5 . 10
= 3 . 1000 + 2 . 100 + 5 . 10
= 3000 + 200 + 50
= 3250
Bài 1:
a: \(7^6+7^5-7^4=7^4\left(7^2+7-1\right)=7^4\cdot55⋮11\)
b: \(10^9+10^8+10^7\)
\(=10^7\left(10^2+10+1\right)=10^7\cdot111⋮111\)
câu a) dễ
43=42.4=42.4.17=42.68
tất cr đề chung thừa số 42 nên
bạn tự tính nha
câu a , b, c , tương tự
\(12+3\cdot3^5:4-3\)
\(=4\cdot3+3^6\cdot\dfrac{1}{4}-3\)
\(=3\cdot\left(4+3^5\cdot\dfrac{1}{4}-1\right)\)
\(=3\cdot\left(3+3^5\cdot\dfrac{1}{4}\right)\)
\(=3\cdot3\cdot\left(1+3^4\cdot\dfrac{1}{4}\right)\)
\(=9\cdot\dfrac{85}{4}\)
\(=\dfrac{785}{4}\)
_________________
\(90^3-88\cdot3\cdot3^9\cdot3\)
\(=9^3\cdot10^3-88\cdot3^{11}\)
\(=\left(3^2\right)^3\cdot10^3-88\cdot3^{11}\)
\(=3^6\cdot1000-88\cdot3^{11}\)
\(=3^6\cdot\left(1000-88\cdot3^5\right)\)
\(=3^6\cdot-20384\)
\(=-14859936\)
________________
\(10^2+10^3+10^4+10^5+10^6\)
\(=\left(10^2+10^3\right)+\left(10^4+10^5\right)+10^6\)
\(=10^2\cdot\left(1+10\right)+10^4\cdot\left(1+10\right)+10^6\)
\(=11\cdot\left(10^2+10^4\right)+10^6\)
\(=11\cdot\left(100+10000\right)+10^6\)
\(=11\cdot10100+1000000\)
\(=111100+1000000\)
\(=1111100\)
_______________
\(7-3:2\cdot7^{10}\)
\(=7\cdot\left(1-\dfrac{3}{2}\cdot7^9\right)\)
\(=7\cdot-60530409,5\)
\(=-423712866,5\)