Toán Lớp 6: a) -12+3.(x+7)=-18 b) 24:(3x-2)=-3 c) -45:5.(-3-2.x)=3 d)(2x-5)+7=6 e)10-2.(4-x)=-4

Question

Toán Lớp 6:  a) -12+3.(x+7)=-18 b) 24:(3x-2)=-3 c) -45:5.(-3-2.x)=3 d)(2x-5)+7=6 e)10-2.(4-x)=-4

lanhuongthu · Answer

Lời giải và giải thích chi tiết:     a,-12+3.(x+7)=-18                3.(x+7)=-18+12                3.(x+7)=-6                   (x+7)=-6:3                    x+7 =-2                    x    =-2-7                    x    =-9     b,24:(3x-2)=-3             (3x-2)=24:(-3)               3x-2=-8               3x =-8+2               3x =-6                 x =-6:3                 x =-2     c, -45:5.(-3-2.x)=3         -45:(-3-2.x)=5.3         -45:(-3-2.x)=15                  -3-2.x=-45:15                -3-2.x=-3                   -2.x=-3+3                   -2.x=0                       x=0     mik c&oacute; việc bận sorry

ngoclankhue · Answer

a) - 12 + 3(x + 7) = - 18 <=> 3(x + 7) = 12 - 18 <=> 3(x + 7) = - 6 <=> x + 7 = (- 6) : 3 <=> x + 7 = - 2 <=> x = - 2 - 7 <=> x = - 9 $ $ b) 24 : (3x - 2) = - 3 <=> 3x - 2 = 24 : (- 3) <=> 3x - 2 = - 8 <=> 3x = 2 - 8 <=> 3x = - 6 <=> x = - 2 $ $ c) (- 45) : 5(- 3 - 2x) = 3 <=> 5(- 3 - 2x) = (- 45) : 3 <=> 5(- 3 - 2x) = - 15 <=> - 3 - 2x = (- 15) : 5 <=> - 3 - 2x = - 3 <=> 2x = - 3 - (- 3) <=> 2x = - 3 + 3 <=> 2x = 0 <=> x = 0 $ $ d) (2x - 5) + 7 = 6 <=> 2x - 5 = 6 - 7 <=> 2x - 5 = - 1 <=> 2x = 5 - 1 <=> 2x = 4 <=> x = 2 $ $ e) 10 - 2(4 - x) = - 4 <=> 2(4 - x) = 10 - (- 4) <=> 2(4 - x) = 10 + 4 <=> 2(4 - x) = 14 <=> 4 - x = 7 <=> x = 4 - 7 <=> x = - 3 $#Ling$