Toán Lớp 6: a)4.(x+25)-125=135 b)25%x+5x-3x=3 1/2-3 1/2 c)(2x-4,5).1 4/7=-11/14 d)16.18-16.7/15.33+33-5 1/2.x=2

Question

Toán Lớp 6:  a)4.(x+25)-125=135 b)25%x+5x-3x=3 1/2-3 1/2 c)(2x-4,5).1 4/7=-11/14 d)16.18-16.7/15.33+33-5 1/2.x=2

buianhtuan · Answer

a) 4 ( x + 25) - 125 = 135   4(x + 25) = 135 + 125   4( x + 25) =  260   ( x + 25)  = 260 : 4   x + 25 = 65   x = 65 - 25   x =  40   Vậy x = 40      b) 25% . x + 5 . x - 3 . x = 3 1/2 - 3 1/2   1/4 . x + 5 . x - 3 . x = 0   ( 1/4 + 5 - 3) . x = 0   9/4 . x = 0   x = 0 : 9/4   x= 0   Vậy x = 0      c) ( 2x - 4,5) . 1 4/7 = -11/14   (2x - 9/2) . 11/7 = -11/14   (2x - 9/2) = -11/14 : 11/7   2x - 9/2 =-1/2   2x = -1/2 + 9/2   2x = 4   x = 4 : 2   x = 2   Vậy x = 2      d) (16 . 18 - 16 . 7)/(15 . 33 + 33) - 5 1/2 . x = 2   (16 . ( 18 - 7))/((15 + 1) . 33) - 11/2 . x = 2   ( 16 . 11)/( 16 . 33)  - 11/2 . x = 2   (1 . 1)/(1 . 3) - 11/2 . x =2   1/3 - 11/2 . x = 2   11/2 . x = 1/3 - 2   11/2 . x= -5/3   x = -5/3 : 11/2   x=-10/33   Vậy x = -10/33

quynhthanhnghi · Answer

a)   4(x + 25) - 125 = 135   &rArr; 4(x + 25) = 135 + 125 = 260   &rArr;  x + 25 = 260 : 4 = 65   &rArr; x = 65 - 25 = 40   b)   25%x + 5x - 3x = 3 1/2 - 3 1/2   &rArr; 1/4x + 2x = 0   &rArr; x . (1/4 + 2) = 0   &rArr; x = 0   c)   (2x - 4,5) . 1 4/7 = -11/14   &rArr; 2x - 4/5 = -11/14 : 11/7 = -1/2   &rArr; 2x = -1/2 + 4/5 = -3/10   &rArr; x = -3/10 : 2 = -3/20   d)   (16 . 18 - 16 . 7)/(15 . 33 + 33) - 5 1/2 . x = 2   &rArr; (16(18 - 7))/(33(15 + 1)) - 11/2 . x = 2   &rArr; 1/3 - 11/2 . x = 2   &rArr; 11/2 . x = 1/3 - 2 = -5/3   &rArr; x = -5/3 : 11/2 = -10/33