1. $x = 6$是下列哪个方程的解?正确的选项是(
A.$3x - 4 = 10$
B.$22 - 3x = 7$
C.$2x + 8 = 20$
D.$25 - 4x = 5$
C
)。A.$3x - 4 = 10$
B.$22 - 3x = 7$
C.$2x + 8 = 20$
D.$25 - 4x = 5$
答案:
C
2. 方程$0.4x + 1.2 = 1.6$的解与下列哪一个方程的解相等?正确的选项是(
A.$2x - 4 = 30$
B.$5x - 6 = 4$
C.$12 - 11x = 1$
D.$13x - 2×6 = 2$
C
)。A.$2x - 4 = 30$
B.$5x - 6 = 4$
C.$12 - 11x = 1$
D.$13x - 2×6 = 2$
答案:
C
3. $x = 3$是哪个方程的解?正确的选项是(
A.$5x - 2 = 13$
B.$12 - 2x = 9$
C.$3x + 4 = 15$
D.$18 - 3x = 6$
A
)。A.$5x - 2 = 13$
B.$12 - 2x = 9$
C.$3x + 4 = 15$
D.$18 - 3x = 6$
答案:
A
二、解方程。
$18x + 24 = 96$ $0.5x - 1.6 = 2.4$
$2x×1.57 = 7.85$ $5x - 4×6 = 48$
$10x + 4.5×8 = 45$ $2.7x - 2×8 = 24.5$
$1.8÷0.3 - 0.2x = 2$ $2.5x - 3.5 = 8.5$
$18x + 24 = 96$ $0.5x - 1.6 = 2.4$
$2x×1.57 = 7.85$ $5x - 4×6 = 48$
$10x + 4.5×8 = 45$ $2.7x - 2×8 = 24.5$
$1.8÷0.3 - 0.2x = 2$ $2.5x - 3.5 = 8.5$
答案:
x=4,x=8,x=2.5,x=14.4,x=0.9,x=15,x=20,x=4.8
三、看图列方程,并求出方程的解。
1.

2.

3.

1.
2.
3.
答案:
1.3x+12=120,x=36 2.2x+4.2×2=12.56,x=2.08 3.3x+27=147,x=40
1. 在每个方程的$□$里填上相同的数,使方程的解都是$x = 2$。
$3x - □ = 0.8 + □$
$0.4x÷□ = 0.8 + 0.4x$
$9×□ - 5x = □ + 11x$
$3x - □ = 0.8 + □$
$0.4x÷□ = 0.8 + 0.4x$
$9×□ - 5x = □ + 11x$
2.6
0.5
4
答案:
2.6,0.5,4
2. 聪聪在做作业时,不小心将$6x - $
$= 0.5x + 27$中等号左边的数字污染了,看不清楚。他想了想,翻看书后的答案,得知方程的解为$x = 8$,于是他很快就知道了这个数字,并迅速地完成了作业。你知道被污染的数字是多少吗?
答案:
6×8-
=0.5×8+27,
=17
6×8-
3. 方程$7x - □ = 2x + □ + 10的解为x = 4$,求$□$的值。
5x=2□+10,5×4=2□+10,□=5
答案:
5x=2□+10,5×4=2□+10,□=5
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