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a, A = 3,5 + |x - 2017| - 9
= -5,5 + |x - 2017|
Ta có : |x - 2017| \(\ge0\Rightarrow-5,5+\left|x-2017\right|\ge-5,5\)
Dấu ''='' xảy ra <=> x - 2017 = 0 <=> x = 2017
Vậy GTNN của A = -5,5 <=> x = 2017
@Cô Bé Dễ Thương
\(B=1x\frac{7}{20}:2,7+2,7:1,35+\left(0,4+2\frac{1}{2}\right)x\left(4,2-1\frac{3}{10}\right)\)
\(B=\frac{7}{20}:2,7+2+2,9x2,9\)
\(B=\frac{7}{54}+2+8,41\)
\(B=10,53962963\)
a) \(10^{10}\cdot\left(-10\right)^4=10^{10}\cdot10^4=10^{10+4}=10^{14}\)
b) \(\left(-2\right)\cdot\left(-2\right)\cdot\left(-2\right)\cdot\left(-2\right)\cdot\left(-2\right)+2^5=\left(-2\right)^5+2^5=0\)
c) \(\left(-3\right)\cdot\left(-3\right)\cdot\left(-3\right)\cdot\left(-3\right)-3^4=\left(-3\right)^4-3^4=81-81=0\)
a) \(1\dfrac{7}{20}:2,7+2,7:1,35+\left(0,4:2\dfrac{1}{2}\right).\left(4,2-1\dfrac{3}{40}\right)\)
\(=\dfrac{27}{20}:\dfrac{27}{10}+\dfrac{27}{10}:\dfrac{27}{10}+\left(\dfrac{2}{5}:\dfrac{5}{2}\right).\left(\dfrac{21}{5}-\dfrac{43}{40}\right)\)
\(=1+1+\dfrac{4}{25}.\dfrac{25}{8}\)
\(=2+\dfrac{1}{2}\)
\(=2\dfrac{1}{2}\)
b) \(\left(6\dfrac{3}{5}-3\dfrac{3}{14}\right).5\dfrac{5}{6}:\left(21-1.25\right):2,5\)
\(=\left(\dfrac{33}{5}-\dfrac{45}{14}\right).\dfrac{35}{6}:\left(-4\right):2,5\)
\(=\left(\dfrac{462}{60}-\dfrac{225}{60}\right).\dfrac{35}{6}.\dfrac{1}{-4}:\dfrac{5}{2}\)
\(=\dfrac{237}{60}.\dfrac{35}{6}.\dfrac{1}{-4}.\dfrac{2}{5}\)
\(=\dfrac{3.79.7.5.2}{5.14.3.2.\left(-4\right).5}\)
\(=\dfrac{79.7}{14.\left(-4\right).5}=\dfrac{553}{-280}\) (số xấu :v)
1. A = (-2)(-3) - 5.|-5| + 125.\(\left(-\dfrac{1}{5}\right)^2\)
= 6 - 25 + 125.\(\dfrac{1}{25}\)
= -19 + 5
= -14
@Shine Anna
a ) Ta có : 4(x - 5) - 3(x + 7) = -19
<=> 4x - 20 - 3x - 21 = -19
=> x - 41 = -19
=> x = -19 + 41
=> x = 22
b) Ta có " 7(x - 3) - 5(3 - x) = 11x - 5
<=> 7x - 21 - 15 + 5x = 11x - 5
<=> 12x - 36 = 11x - 5
=> 12x - 11x = -5 + 36
=> x = 31
a)
3,2 . x + ( -1,2 ) . x + 2,7 = -4,9
x . ( 3,2 - 1,2 ) + 2,7 = -4,9
x . 2 + 2,7 = -4,9
x . 2 = -4,9 - 2,7
x . 2 = -7,6
x = -7,6 : 2
x = -3,8
b) ( -5,6 ) . x + 2,9 . x - 3,86 = -9,8
x . ( -5,6 + 2,9 ) - 3,86 = -9,8
x . ( -2,7 ) - 3,86 = -9,8
x . ( -2,7 ) = -9,8 + 3,86
x . ( -2,7 ) = -5,94
x = ( -5,94 ) : ( -2,7 )
x = 2,5
a) 3,2 x + (-1,2) x +2,7 = -4,9
x(3,2 +-1.2 ) +2,7 =-4,9
x . 2 +2,7 =-4,9
x.2 = -7,6
x= -3,8.
b) (-5,6) . x + 2,9 x - 3,86 = -9,8
x (-5,6 + 2,9) - 3,86 = -9,8
x. -2,7 = -5,94
x =2,2
\(\left[\left(-2,7\right)^4\right]^5-\left[\left(-2,7\right)^2\right]^{10}\)
\(=\left[\left(-2,7\right)^4\right]^5-\left[\left(-2,7\right)^2\right]^{2.5}\)
\(=\left[\left(-2,7\right)^4\right]^5-\left[\left(-2,7\right)^4\right]^5=0\)
Vậy..............