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Bài 1:
a,\(0,75+\frac{9}{17}-1\frac{4}{5}-\frac{26}{17}-2\frac{4}{5}\)
\(=\frac{3}{4}+\left(\frac{9}{17}-\frac{26}{17}\right)-\left(1\frac{4}{5}+2\frac{4}{5}\right)\)
\(=\frac{3}{4}-1-\frac{23}{5}\)
\(=\frac{15}{20}-\frac{20}{20}-\frac{92}{20}=\frac{-97}{20}\)
Bài 2:
a, \(\left(2x+\frac{3}{4}\right)-\frac{10}{3}=\frac{-13}{3}\)
\(2x+\frac{3}{4}=\frac{-13}{3}+\frac{10}{3}\)
\(2x+\frac{3}{4}=-1\)
\(2x=-1-\frac{3}{4}\)
\(2x=\frac{-7}{4}\)
x = -7/8
b, 3,2x - 2,7x + 8,5 = 6
x(3,2 - 2,7) = -2,5
0,5x = -2,5
x = -5
\(=\)\(\frac{1}{2}\)-\(\frac{-13}{6}\)-\(\frac{5}{6}\)
\(=\)\(\frac{3}{6}\)-\(\frac{-13}{6}\)-\(\frac{5}{6}\)
\(=\)\(\frac{11}{6}\)
\(\frac{3}{4}-0,25-\left(\frac{7}{3}+\frac{-9}{2}\right)-\frac{5}{6}\)
\(=\frac{3}{4}-\frac{1}{4}-\left(\frac{14}{6}+\frac{-27}{6}\right)-\frac{5}{6}\)
\(=\frac{1}{2}-\frac{-13}{6}-\frac{5}{6}\)
\(=\frac{3}{6}+\frac{13}{6}-\frac{5}{6}\)
\(=\frac{16}{6}-\frac{5}{6}\)
\(=\frac{11}{6}\)
( 2x - 3 )2 = 16
( 2x - 3 )2 = 42 hoặc (-4)2
=> 2x - 3 = 4 hoặc 2x - 3 = -4
2x = 4+3 2x = -4 + 3
2 x = 7 2x = -1
x = 7/2 x = -1/2
~ Ko bt đúng ko, ko chắc lắm ~
( 2x -3 )2 = 16
( 2x - 3 )2 = 24
2x - 3 = 2
2x =2 + 3
2x = 5
x 5:2
==> x = ko có gt x
k nha bn
a/ S = ( - 2/3 + 1) - (7/5 - 0,2) + )7/15 - 1 + 4/3) = - 2/3 + 1 - 7/5 + 1/5 +7/15 - 1 + 4/3 = 2/3 - 6/5 + 7/15 = 10/15 - 18/15 + 7/15 = - 1/15.
b/ S = 0,25 - 9- (- 3/4) - [ - 7/3 + (-9/2)] - 5/6 = 1/4 - 9 + 3/4 + 7/3 + 9/2 - 5/6 = - 8 + 14/6 + 27/6 - 5/6 = - 8 + 6 = - 2
\(S=\frac{3}{4}-0,25-\left[\frac{7}{3}+\left(\frac{-9}{2}\right)\right]-\frac{5}{6}\)
\(\Rightarrow S=\frac{3}{4}-\frac{1}{4}-\left(\frac{7}{3}-\frac{9}{2}\right)-\frac{5}{6}\)
\(\Rightarrow S=\frac{1}{2}-\frac{7}{3}+\frac{9}{2}-\frac{5}{6}\)
\(\Rightarrow S=\frac{3}{6}-\frac{14}{6}+\frac{27}{6}-\frac{5}{6}\)
\(\Rightarrow S=\frac{11}{6}\)
(-10/3)^5 . (-6/5)^4
= (-10/3)^4.(-10/3).(-6/5)^4
= [(-10/3).(-6/5)]^4.(-10/3)
= 4^4 . (-10/3)
= 256.(-10/3)
= -2560/3
(3/7)^21:(9/49)^6
=(3/7)^21:[(3/7)^2]^6
=(3/7)^21:(3/7)^12
=(3/7)^21-12
=(3/7)^9
3/4-0,25-[7/3+(-9/2)]-5/6
=3/4-0,25-(-13/6)-5/6
=0,5+13/6-5/6
=8/3-5/6
=11/6