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\(\frac{\left(\frac{5^9}{5^{17}}+3\right)}{7}\)= \(\frac{\left(\frac{1}{5^8}+3\right)}{7}\)= \(\frac{\left(\frac{1171876}{390625}\right)}{7}\)= 0.4285717943
\(\frac{7^9}{7^7}-3^2+2^3.5^2\)= \(7^2-3^2+2^3.5^2\)= \(7^2-3^2+200\)= \(40+200=240\)
\(\frac{5^9}{5^7}+\frac{70}{14}-20\)= \(5^2+5-20\)=\(30-20=10\)
\(\frac{2^{28}}{2^{26}}+5^1.3^2-7^2\)= \(2^2+5.3^2-7^2\)= \(4+45-49\)= \(0\)
a) ( 519 : 517 + 3 ) : 7
= ( 25 + 3 ) : 7
= 28 : 7
= 4
b) 79 : 77- 32 + 23 . 52
= 49 - 9 + 8 . 25
= 49 - 9 + 200
= 40 + 200
= 240
c) 1200 : 2 + 62 . 21 + 18
= 600 + 36 . 2 + 18
= 600 + 72 + 18
= 672 + 18
= 690
d) 59 : 57 + 70 : 14 - 20
= 25 + 70 : 14 - 20
= 25 + 5 - 20
= 30 - 20
= 10
e) 100 : 52 + 7 . 32
= 100 : 25 + 7 . 9
= 4 + 63
= 67
f ) 84 : 4 + 39 : 37 + 50
= 21 + 9 + 1
= 30 + 1
= 31
Mình xin giải như sau:
a)15x-57=3^14:3^9
15.x-57=3^5
15.x-57=243
15.x=243+57
15.x=300
x=300:15
x=20
b)50-[70:(x-1)]=15
70:(x-1)=50-15
70:(x-1)=35
x-1=70:35
x-1=2
x=2+1
x=3
c) (5^2+2^3).x+4^2=7^2
(25+8).x+16=49
33.x=49-16
33.x=33
x=33:33
x=1
d) 2^x:2^5=1
2^x=1.2^5
2^x=2^5
Suy ra x=5
18-(x-2)^5=2.3^2
18-(x-2)^5=2.9
18-(x-2)^5=18
(x-2)^5=18-18
(x-2)^5=0
x=0+2
x=2
\(5^2-\left(5.3^3-4.2^3\right).19=25-\left(135-32\right).19=25-103.19=25-1957=-1932\)
\(215-\left(5^2.2^3+700\right):3^2=215-\left(200+700\right):3^2=215-900:9=215-100=115\)
\(16.25+2^4.75=400+1200=1600\)
\(15.2^3+4.3^2-5.7=120+36-35=121\)