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a) \(2\left|x\right|-5=3\)
=> \(2\left|x\right|=3+5\)
=> \(2\left|x\right|=8\)
=> \(\left|x\right|=4\)
=> x = 4 hoặc x = -4
b) \(x-5=\left(-14\right)+2^3\)
=> \(x-5=\left(-14\right)+8\)
=> \(x-5=-6\)
=> \(x=-6+5=-1\)
c) \(10+2x=4^5:4^3\)
=> \(10+2x=4^{5-3}\)
=> \(10+2x=4^2\)
=> \(2x=4^2-10=16-10=6\)
=> \(2x=6\)
=> \(x=3\)
d) (x + 7) - 13 = 4
=> x + 7 = 17
=> x = 17 - 7 = 10
e) \(2x-10=2^4:2^2\)
=> \(2x-10=2^2\)
=> \(2x-10=4\)
=> \(2x=14\)
=> \(x=7\)
a) \(\left(9^4.8+9^4.5\right):\left(9^2.\left(10-1\right)\right)\)
=\(9^4.13:9^3=13.9=117\)
b) 100-(75-25)=100-50=50
Đặt \(A=\frac{1.2+2.4+3.6+4.8+5.10}{4+6.8+9.12+12.16+15.20}\)
\(\Rightarrow A=\frac{1.\left(1+2\right)+2.\left(1+2\right)+3.\left(1+2\right)+4.\left(1+2\right)+5.\left(1+2\right)}{4+2.\left(3+4\right)+3.\left(3+4\right)+4.\left(3+4\right)+5.\left(3+4\right)}\)
\(\Rightarrow A=\frac{\left(1+2+3+4+5\right).\left(1+2\right)}{4+\left(2+3+4+5\right).\left(3+4\right)}\)
\(\Rightarrow A=\frac{\left(1+5\right).5:2.\left(1+2\right)}{4+\left(2+5\right).4:2.\left(3+4\right)}\)
\(\Rightarrow A=\frac{6.5:2.3}{4+7.4:2.7}=\frac{45}{4+98}=\frac{45}{102}=\frac{15}{34}\)
Vậy \(A=\frac{15}{34}\)
Chúc bn học tốt
3 x 8/15 x 12 = 3x8/15 x12 = 24/15 x 12 = 288/15
7 x 25-49/7 x 24+21= 175 - 7 x24 + 21 =4053
2 x (-13) x 9 x 10/(-3) x 4 x (-5) x 26= -26 x 9 x 10 / 1560 = -234 x 1/156 = -3/2
a)=1/2 . 8/15 - 3/4.47/9
=4/15 - 47/12
=-73/20
b)=2-1/3 . -21/20
=2+7/20
=47/20
a) 3x4-3x-2x+2=x+20 b) 10+13-(x2- 6x+9)=0
12-5x=x+20 -x2+ 6x+14=0...
6x=-8
x=-3/2