Toán Lớp 7: a, |2x-3|-1=0 b, 2.|3x-1/2|+5=6

Question

Toán Lớp 7:  a, |2x-3|-1=0 b, 2.|3x-1/2|+5=6

buithaianh98 · Answer

Giải đáp:    a, |2x - 3| - 1 = 0       |2x - 3|       = 1   &rArr; ( left[  begin{array}{l}2x - 3 = 1  2x - 3 = -1 end{array}  right. )    &rArr; ( left[  begin{array}{l}x = 2  x = 1 end{array}  right. )    Vậy x  in {2 ; 1}   b, 2 . |3x - 1/2| + 5 = 6      2 . | 3x - 1/2|       = 1            |3x - 1/2|       = 1/2   &rArr; ( left[  begin{array}{l}3x -  frac{1}{2} =  frac{1}{2}  3x -  frac{1}{2} = - frac{1}{2} end{array}  right. )    &rArr; ( left[  begin{array}{l}3x = 1  3x  = 0 end{array}  right. )    &rArr; ( left[  begin{array}{l}x =  frac{1}{3}  x = 0 end{array}  right. )    Vậy x  in{ 1/3 ; 0}

diemchau · Answer

Tr&igrave;nh b&agrave;y lời giải:     a)  |2x-3|-1=0 =>|2x-3|=0+1 =>|2x-3|=1 =>[(2x-3=1),(2x-3=-1):} =>[(2x=1+3),(2x=-1+3):} =>[(2x=4),(2x=2):} =>[(x=4:2),(x=2:2):} =>[(x=2),(x=1):} Vậy x in{2;1} b) 2.|3x-1/2|+5=6 =>2.|3x-1/2|=6-5 =>2.|3x-1/2|=1 =>|3x-1/2|=1:2 =>|3x-1/2|=1/2 =>[(3x-1/2=1/2),(3x-1/2=-1/2):} =>[(3x=1/2+1/2),(3x=-1/2+1/2):} =>[(3x=1),(3x=0):} =>[(x=1/3),(x=0):} Vậy x in{1/3;0}