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(1374.57+687.86): (26.13+74.14)
=(687.2.57+687.86): (26.13+74.14)
=(687.114+687.86): (26.13+74.14)
=[(114+86).687]: (26.13+74.14)
= 200 . 687]: (26.13+74.14)
= 137400 : (26.13+74.14)
= 137400 : ( 338+1036 )
= 137400 : 1374
= 100
a) (-2,5. 0,38. 0, 4) - ( 0,125. 3,15. (-8))
=((-2,5.0,4).0,38) - ((-8.0,125).3,15)
= ((-1).0,38) - ((-1).3,15)
= -0,38 - (-3,15)
= 2.77
b) ((-20,83) .0,2 + (-9,17).0,2) : ( 2,47.0,5 - (-3,53).0,5)
= ((-20,83 - 9,17).0,2) : ((2,47 + 3,53).0,5)
= (-6) : 3
= -2
a) (-2,5. 0,38. 0, 4) - ( 0,125. 3,15. (-8))
=((-2,5.0,4).0,38) - ((-8.0,125).3,15)
= ((-1).0,38) - ((-1).3,15)
= -0,38 - (-3,15)
= 2.77
b) ((-20,83) .0,2 + (-9,17).0,2) : ( 2,47.0,5 - (-3,53).0,5)
= ((-20,83 - 9,17).0,2) : ((2,47 + 3,53).0,5)
= (-6) : 3
= -2
a) [(-2,5. 0,38. 0, 4) - ( 0,125. 3,15. (-8)]
=[(-2,5.0,4).0,38] - [(-8.0,125).3,15)]
= [(-1).0,38] - [(-1).3,15]
= -0,38 - (-3,15)
= 2.77
b) [(-20,83) .0,2 + (-9,17).0,2] : [ 2,47.0,5 - (-3,53).0,5]
= [(-20,83 - 9,17).0,2] : [(2,47 + 3,53).0,5]
= (-6) : 3
= -2
a/ \(\left(-2,5.0,38.0,4\right)-\left[0,125.3,15.\left(-8\right)\right]\)
\(=\left(-0,95.0,4\right)-\left[0,39375.\left(-8\right)\right]\)
\(=-0,38-3,15=2,77\)
b/ \(\left[\left(-20,83\right).0,2+\left(-9,17\right).0,2\right]:\left[2,47.0,5-\left(-3,53\right).0,5\right]\)
\(=\left[-4,166+-1,834\right]:\left[1,235--1,765\right]\)
\(=-6:3\)
\(=-2\)
\(\left(-2\right).\left(-1\frac{1}{2}\right)\left(-1\frac{1}{3}\right).....\left(-1\frac{1}{2013}\right)\)
\(=\left(-2\right).\left(\frac{-3}{2}\right)\left(-\frac{4}{3}\right)......\left(\frac{-2014}{2013}\right)\)
\(=\frac{\left(-2\right).\left(-3\right).\left(-4\right)....\left(-2014\right)}{2.3.....2013}\)
\(=\frac{2.3.4....2014\left(\text{Vì có 2014 thừa số âm }\right)}{2.3....2013}\)
\(=\frac{\left(2.3.4....2013\right).2014}{2.3....2013}\)
\(=2014\)
\(\left(x^2-1\right).\left(x^2-9\right)\)
\(=x^4-9x^2-x^2+9\)
\(=x^4-10x^2+9\)
\(=\left(x^2\right)^2-2.x^2.5+25-16\)
\(=\left(x^2-5\right)^2-16\ge-16\)
=> GTNN của B.thức trên là -16
<=> \(x^2-5=0\Leftrightarrow x^2=5\Leftrightarrow x=\sqrt{5}\text{ hoặc }x=-\sqrt{5}\)
Vậy...
\(\left(2x+1\right)\left(3x-\frac{9}{2}\right)=0\Leftrightarrow2x+1=0;3x-\frac{9}{2}=0\Leftrightarrow x=-0,5;x=1,5\Rightarrow x\in\left\{-0,5;1,5\right\}\)
\(1990\times1990-1992\times1998\)
\(=1990\times1990-\left(1992-2\right)\times\left(1998+2\right)\)
\(=1990\times1990-1990\times1990\)
\(=0\)
\(1990\times1990-1992\times1998\)
\(=1990\times1990-\left(1992-2\right)\times\left(1998+2\right)\)
\(=1990\times1990-1990\times2000\)
\(=3960100-3980000\)
\(=-1990.\)