Toán Lớp 6: e) 12 – x = x + 4 f) 14 + 4x = 3x + 20 g) 3(x – 2) + 2x = 10

Question

Toán Lớp 6:  e) 12 – x = x + 4                                                          f) 14 + 4x = 3x + 20       g) 3(x – 2) + 2x = 10                                                   h) 2.(x-1) + 3(x-2) = 2 giúp em zới

lanhuongthu · Answer

$e)$ $12-x=x+4$   $&rArr;12-x-12=x+4-12$   $&rArr;-x=x-8$   $&rArr;-x-x=x-8-x$   $&rArr;-2x=-8$   $&rArr; dfrac{-2x}{-2}= dfrac{-8}{-2}$   $&rArr;x=4$   ________________________________________________   Vậy $x=4$   $f)$ $14+4x=3x+20$   $&rArr;14+4x-14=3x+20-14$   $&rArr;4x=3x+6$   $&rArr;4x-3x=3x+6-3x$   $&rArr;x=6$   Vậy  $x=6$   ____________________________________________   $g)$ $3 left(x-2 right)+2x=10$   $&rArr;5x-6=10$   $&rArr;5x-6+6=10+6$   $&rArr;5x=16$   $&rArr; dfrac{5x}{5}= dfrac{16}{5}$   $&rArr;x= dfrac{16}{5}$   Vậy $x= dfrac{16}{5}$   _____________________________________________________________________   $h)$  $2 cdot  left(x-1 right) :+ :3 left(x-2 right) := :2$   $&rArr;5x-8=2$   $&rArr;5x-8+8=2+8$   $&rArr;5x=10$   $&rArr; dfrac{5x}{5}= dfrac{10}{5}$   $&rArr;x=2$   Vậy $x=2$   __________________________________________________________________   $i)$ $4 left(2x+7 right)-3 left(3x-2 right)=24$   $&rArr;-x+34=24$   $&rArr;-x+34-34=24-34$   $&rArr;-x=-10$   $&rArr; dfrac{-x}{-1}= dfrac{-10}{-1}$   $&rArr;x=10$   Vậy $x=10$   _________________________________________________________   $k)$ $3 left(4-x right)-2 left(x-1 right)=x+20$   $&rArr;-5x+14=x+20$   $&rArr;-5x+14-14=x+20-14$   $&rArr;-5x=x+6$   $&rArr;-5x-x=x+6-x$   $&rArr;-6x=6$   $&rArr; dfrac{-6x}{-6}= dfrac{6}{-6}$   $&rArr;x=-1$   Vậy $x=-1$

tuanh · Answer

$e)$ $12-x=x+4$   $&rArr;12-x-12=x+4-12$   $&rArr;-x=x-8$   $&rArr;-x-x=x-8-x$   $&rArr;-2x=-8$   $&rArr; dfrac{-2x}{-2}= dfrac{-8}{-2}$   $&rArr;x=4$   Vậy $x=4$   $----------------$   $f)$ $14+4x=3x+20$   $&rArr;14+4x-14=3x+20-14$   $&rArr;4x=3x+6$   $&rArr;4x-3x=3x+6-3x$   $&rArr;x=6$   Vậy  $x=6$   $----------------$   $g)$ $3 left(x-2 right)+2x=10$   $&rArr;5x-6=10$   $&rArr;5x-6+6=10+6$   $&rArr;5x=16$   $&rArr; dfrac{5x}{5}= dfrac{16}{5}$   $&rArr;x= dfrac{16}{5}$   Vậy $x= dfrac{16}{5}$   $----------------$   $h)$  $2 cdot  left(x-1 right) :+ :3 left(x-2 right) := :2$   $&rArr;5x-8=2$   $&rArr;5x-8+8=2+8$   $&rArr;5x=10$   $&rArr; dfrac{5x}{5}= dfrac{10}{5}$   $&rArr;x=2$   Vậy $x=2$   $----------------$   $i)$ $4 left(2x+7 right)-3 left(3x-2 right)=24$   $&rArr;-x+34=24$   $&rArr;-x+34-34=24-34$   $&rArr;-x=-10$   $&rArr; dfrac{-x}{-1}= dfrac{-10}{-1}$   $&rArr;x=10$   Vậy $x=10$   $----------------$   $k)$ $3 left(4-x right)-2 left(x-1 right)=x+20$   $&rArr;-5x+14=x+20$   $&rArr;-5x+14-14=x+20-14$   $&rArr;-5x=x+6$   $&rArr;-5x-x=x+6-x$   $&rArr;-6x=6$   $&rArr; dfrac{-6x}{-6}= dfrac{6}{-6}$   $&rArr;x=-1$   Vậy $x=-1$