Toán Lớp 6: Tìm x: a) 200 – 8.(2x + 7) = 112 b) (2x – 123):3 = 33

Question

Toán Lớp 6:  Tìm x: a) 200 – 8.(2x + 7) = 112 b) (2x – 123):3 = 33

tuenhioanh · Answer

Giải đáp:    $a) 200-8.(2x+7)=112$   $&hArr; 8.(2x+7)=200-112$   $&hArr; 8.(2x+7)= 88$   $&hArr; 2x+7=88:8$   $&hArr; 2x+7=11$   $&hArr; 2x=4$   $&hArr; x=4:2$   $&hArr; x=2$   $Vậy$ $x=2$   $b) (2x-123):3=33$   $&hArr; 2x-123= 33.3$   $&hArr; 2x-123=99$   $&hArr; 2x= 99+123$   $&hArr; 2x=222$   $&hArr; x=222:2$   $&hArr; x=111$   $Vậy$ $x=111$

quynhmaithu · Answer

T&igrave;m x:            a) 200 &ndash; 8.(2x + 7) = 112           -8.(2x + 7) = 112 &ndash; 200           -8.(2x + 7) = -88               2x + 7 = (-88):(-8)           2x + 7 = 11           2x = 11 &ndash; 7           2x = 4           x = 4:2               x = 2           b) (2x &ndash; 123):3 = 33           2x &ndash; 123 = 33.3          2x &ndash; 123 = 99         2x = 99 + 123              2x = 222           x = 222:2           x = 111