Tìm x, biết:
a) \({1 \over 3} + x = {3 \over 4}\) b) \( - {2 \over 5} - x = {{ - 3} \over 8}\)
c) \(x - {2 \over 3} = - {3 \over 4}\) d) \( - {4 \over 5} - {1 \over 2} = - x\)
e) \({3 \over 2}x - {4 \over 5} = {1 \over 2}x\)
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\(\eqalign{ & a){1 \over 3} + x = {3 \over 4} \cr & x = {3 \over 4} - {1 \over 3} \cr & x = {9 \over {12}} - {4 \over {12}} \cr & x = {5 \over {12}} \cr & b) - {2 \over 5} - x = {{ - 3} \over 8} \cr & {{ - 2} \over 5} + {3 \over 8} = x \cr & {{ - 16} \over {40}} + {{15} \over {40}} = x \cr & x = - {1 \over {40}} \cr & c)x - {2 \over 3} = - {3 \over 4} \cr & x = {{ - 3} \over 4} + {2 \over 3} \cr & x = {{ - 9} \over {12}} + {8 \over {12}} \cr & x = {{ - 1} \over {12}} \cr & d) - {4 \over 5} - {1 \over 2} = - x \cr & x = {4 \over 5} + {1 \over 2} \cr & x = {8 \over {10}} + {5 \over {10}} \cr & x = {{13} \over {10}} = 1{3 \over {10}} \cr & e){3 \over 2}x - {4 \over 5} = {1 \over 2}x \cr & {3 \over 2}x - {1 \over 2}x = {4 \over 5} \cr & \left( {{3 \over 2} - {1 \over 2}} \right)x = {4 \over 5} \cr & x = {4 \over 5} \cr} \)