Toán Lớp 7: 1) 5/2-1/2|x-1|=1/3

Question

Toán Lớp 7:  1) 5/2-1/2|x-1|=1/3                                                                                                                                                2) 1 1/2 - |x-2|=-5/3                                                                                                                                            3) 3/4-2/5x=29/60                                                                                                                                                   4) 2x -1/3 =-5/6

thuminhthong · Answer

a)  5/2 - 1/2 | x - 1 | = 1/3   1/2 &times; | x - 1 | = 5/2 - 1/3   1/2 &times; | x - 1 | = 13/6   | x - 1 |= 13/3                 TH1   x = 13/3 + 1   x = 16/3   | x - 1 | = -13/3              TH2   x = -13/3 + 1   x = -10/3   => x = 16/3 ; -10/3    b)  1 1/2 - | x - 2 | = -5/3   3/2 + (-x) + (-2) = -5/3   [ 3/2 + (-2) ] + (-x) = -5/3   -1/2 + (-x) = -5/3   -x = -5/3 - (-1)/2   -x = -7/6   => x = 7/6    c)  3/4 - 2/5x = 29/60   2/5x = 3/4 - 29/60   2/5x = 4/15   x = 4/15 : 2/5   x = 2/3    d)  2x - 1/3 = -5/6   2x = -5/6 + 1/3   2x = -1/2   x = -1/2 : 2   x = -1/4   @ Rin

tuanh · Answer

Giải đáp + Lời giải và giải thích chi tiết:      1) 5/2 - 1/2|x-1|=1/3   &rArr; 1/2|x-1|=5/2-1/3   &rArr; 1/2|x-1|=13/6   &rArr; |x-1| = 13/3   &rArr;  ( left[  begin{array}{l}x-1= frac{13}{3}  x-1= frac{-13}{3} end{array}  right. )    &rArr;  ( left[  begin{array}{l}x= frac{16}{3}  x-1= frac{-10}{3} end{array}  right. )    2) 1 1/2 - |x-2|=-5/3   &rArr; 3/2- |x-2|=-5/3   &rArr; |x-2|=-1/6   &rArr; x &isin; O/ (v&igrave; |x-2| &ge; 0; -1/6 < 0)   3)  3/4 -2/5x=29/60     &rArr; 2/5x=4/15     &rArr; x=4/15 : 2/5 = 2/3     4) 2x -1/3 =-5/6     &rArr; 2x=-5/6 + 1/3     &rArr; 2x=-1/2     &rArr; x=-1/2 : 2=-1/4