Toán Lớp 7: |5x-4|=|x+2| |2x-3|-|3x+2|=0 |2+3x|=|4x-3|

Question

Toán Lớp 7:  |5x-4|=|x+2| |2x-3|-|3x+2|=0 |2+3x|=|4x-3|

giangnguyen33 · Answer

Giải đáp:   $  $   a,    |5x-4| = |x+2|    ->  ( left[  begin{array}{l}5x-4=x+2  5x-4=-x-2 end{array}  right. )   ->   ( left[  begin{array}{l}5x-x=4+2  5x+x=4-2 end{array}  right. )   ->   ( left[  begin{array}{l}4x=6  6x=2 end{array}  right. )    ->  ( left[  begin{array}{l}x= dfrac{3}{2}  x= dfrac{1}{3} end{array}  right. )    Vậy x=3/2 hoặc x=1/3   b,   |2x-3|-|3x+2|=0   ->|2x-3|=|3x+2|   ->  ( left[  begin{array}{l}2x-3=3x+2  2x-3=-3x-2 end{array}  right. )   ->  ( left[  begin{array}{l}2x-3x=3+2  2x+3x=3-2 end{array}  right. )   ->  ( left[  begin{array}{l}-x=5  5x=1 end{array}  right. )   ->  ( left[  begin{array}{l}x=-5  x= dfrac{1}{5} end{array}  right. )    Vậy x=-5 hoặc x=1/5   c,   |2+3x| = |4x-3|   -> |3x+2|=|4x-3|   ->  ( left[  begin{array}{l}3x+2=4x-3  3x+2=-4x+3 end{array}  right. )   ->  ( left[  begin{array}{l}3x-4x=-2-3  3x+4x=-2+3 end{array}  right. )   ->  ( left[  begin{array}{l}-x=-5  7x=1 end{array}  right. )   ->  ( left[  begin{array}{l}x=5  x= dfrac{1}{7} end{array}  right. )    Vậy x=5 hoặc x=1/7