Toán Lớp 7: 8-I1-3xI=3 1/2-(x+1/3)=5/6 2^x+2^x+4=544 (4/7-1/2x)^3=8

Question

Toán Lớp 7:  8-I1-3xI=3 1/2-(x+1/3)=5/6 2^x+2^x+4=544 (4/7-1/2x)^3=8

lantrungbach · Answer

a)   ->| 1-3x| = 3-8   ->|1-3x |= -5   ->|1-3x | =5   -> 1-3x=5 hoặc 1-3x=-5   -> 3x=1-=-4 hoặc 3x=1--5=6   b)   -> 1/2-x-1/3=5/6   -> 1/6-x=5/6   -> -x= 5/6-1/6   -> -x=2/3   Vậy x= -2/3   c)   4x+4x+4=544   -> 8x+4=544   -> 8x= 544-4   -> 8x=540   -> x= 135/2   d)   ->(4/7-1/2x)^3=2^3   -> 4/7-1/2x= 2   -> 8-7x=28    -> -7x= 28-8   -> -7x= 20   -> x= -20/7   #tcv

tongtung · Answer

8-I1-3xI=3      -> -/ 1-3x/ = 3-8     -> / 1-3x /= -5     -> / 1-3x / =5     -> 1-3x=5 hoặc 1-3x=-5     -> x1= -4/3, x2= 2     1/2-(x+1/3)=5/6    -> 1/2-x-1/3=5/6   -> 1/6-x=5/6   -> -x= 5/6-1/6   -> -x=2/3   Vậy x= -2/3    2^x+2^x+4=544    4x+4x+4=544   -> 8x+4=544   -> 8x= 544-4   -> 8x=540   -> x= 135/2    (4/7-1/2x)^3=8    ->(4/7-1/2x)^3=2^3   -> 4/7-1/2x= 2   -> 8-7x=28 ( quy đồng, mẫu thức chung: 14)   -> -7x= 28-8   -> -7x= 20   -> x= -20/7