小数方程计算专项练习题.docx

1、小数方程计算专项练习题(1)( x+0.55) 4=3.6(9) 36乡=0.4(2) 2x8=0.8(10) 9.6x - x=43(3) 1.5 +2x=5(11) 3x - 4X0.9=46.2(4) 4.7x=1.9x+7(12) 3.5x - 4X7=42(5) 12.6 (x+4.8 )吃=63(13) x- 0.9x=81.9(6) 12.5+4x=21.7(14) 3.8+5x=12.3(7) 13.5x - 8.5x=20(16) 8x - 1.6x=19.2(25) xP.5=48.6 (17) xT8=1.62(26) 5X - 7.8=20.2 ,(18) 22.5 &

2、+5x=135.(27) 2.5X - X=1.8 ,(19) 1.4x+9.8=22.4 ,(28)( 4.5+X ) 2=13 ,(20) 2 ( x- 3) =11.6,(29) 7x - 2X9=80,(21) 68 - 4.4x=24 ,(30) 13x - 7.5x=18.7 ,(22) 1.6 8- 5x=2.3(31)( x+12) 0=108 ,(23) 2.5x -20=16(24) 6.2x - x=41.6(33) 2X (x - 0.5) =1.6(42)2x - 2+1.8=3.6(34)3xX2.34=4.914(43)7 (x - 1.2) =3.57(35)1

3、.44 *=0.4(44)2+1.8 - 2x=3.6(36)2x+6=12.5(45)7x*0.3=4.2(37)2.5x - x=1.2(46)6x+4x - 1仁32.9(38)(4.5+x) 2=63(47)7 (x - 1.2) =2.87(39)2x - 2.5 0=15(48)2.4+3.4x=5.8(40)3.85+1.5x=6.1(49)5 (x - 1.2) =35(41) 13 (x+2.5) =169(50) 2.5X+5仁17 X8(59) 2 (x - 3) =10.6(51) 2.4x+1.6x=2.2(60) 13x - x=14.4(52) 8 ( x- 6.

4、2) =41.6(61) 68 - 1.1x=24(53) 0.5 (x - 0.5) =7.5(62) 3 (x+3.5) =21.6(54)( 9x+1.5+7x )弋=5.1(63) 3x - 54=136.5(55) 3x+7=29.5(64) x- 0.36x=3.2(56) 5x - 2.8 1.2=1.04(65) 4x+2.8 4=19.32(57) 4x+6x=28.5(67) 4.8x+2.6x=3.7(76) 8x - 4x=0.64(68) 3x+6.4 2=50.3(77) 2x - 0.24=0.12(69) 2.7x - 1.8=1.2x+2.7 ,(78)( 3

5、.8 - 2) x=14.4(70) 8 - 5 (6x+0.7) =10x+0.5 ,(79) 64 - 16X=56.8(71) 7畝-0.7=1.3,(80) 8.6X - 2.6X=36.6(72)( 5.9+x) +16=30,(82) 64- 0.6X=6.36(73) 0.56 - 4x=0.4 ,(83) 0.03 50 - 5x=3.2(74) 4 ( x- 0.5) =9.6 ,(84) 45.3 - 4X=35.7 ,(86) 5.9X+7=8.7X ,(88) 0.6 (y 0.4) =6 ,小数方程88题参考答案:(1)( x+0.55) X4=3.6(x+0.5)

6、M韶=3.6 呜x+0.5=0.9x+0.5 0.5=0.9 0.5x=0.4(2)2xP=0.82x 4=0.8 4x=3.2(3)1.5 4+2x=53+2x=53+2x 3=5 32x吃=2吃x=1(4)4.7x=1.9x+7 4.7x 1.9x=1.9x 1.9x+72.8x=72.8x 2.8=7 2.8x=2.5(5)12.6 (x+4.8) 22=636.3 (x+4.8 ) =636.3 ( x+4.8) 26.3=63 6.3x+4.8=10x+4.8 4.8=10 4.8x=5.2 ;12.5+4x=21.74x -4=9.2 -4x=2.3(7) 13.5x - 8.5x

7、=205x为=20为x=4(8)6x - 8.5 冶=206x - 34=206x - 34+34=20+346x .6=54 七x=9(9)36乡=0.436 -x 为=0.4 X36=0.4 X36 弋.4=0.4 x).4x=90 ;(10)9.6x - x=43 (9.6- 1) x=43 8.6x . 6=43 .5x=5;(11)3x - 4X0.9=46.23x- 3.6=46.23x - 3.6+3.6=46.2+3.63x -3=49.8 3x=16.6(12)3.5x - 4X7=423.5x - 28=423.5x - 28+28=42+283.5x=703.5x 3.5

8、=70 3.5 x=20;(13)x- 0.9x=81.90.1x=81.90.1x 0.仁81.9 0.1 x=819;(14)3.8+5x=12.33.8+5x 3.8=12.3 3.85x=8.55x -5=8.5 5 x=1.7;(15)4 ( 0.3+x) =6.84 ( 0.3+x) -4=6.8 4 0.3+x=1.70.3+x 0.3=1.7 0.3x=1.4(16)8x - 1.6x=19.26.4x=19.2 ,6.4x 6.4=19.2 6.4,x=3;(17)x 1.8=1.62x -1.8 X.8=1.62 X8,x=2.916 ;(18)22.5 X+5x=135

9、,45+5x - 45=135 - 45,5x -5=90 -5,x=18 .(19)1.4x+9.8=22.4 ,1.4x+9.8 9.8=22.4 9.8,1.4x=12.6 ,1.4x 1.4=12.6 他， x=9 ;(20)2 (x - 3) =11.6,2x - 6=11.6,2x - 6+6=11.6+6 ,2x=17.6 ,2x-2=17.6 2,x=8.8;(21)68 - 4.4x=24 ,68 - 4.4x+4.4x=24+4.4x ,24+4.4x=68 ,24+4.4x - 24=68 - 24,4.4x=44 ,4.4x 4.4=44 4.4,x=10(22)1.6

10、 X- 5x=2.312.8- 5x+5x=2.3+5x2.3+5x - 2.3=12.8 - 2.35x -5=10.5 5x=2.1 ;(23)2.5x -20=162.5x 20 X0=16 X202.5x 乞.5=320 2.5x=128;(24)6.2x - x=41.65.2x=41.65.2x 5.2=41.6 52x=8;(25)xP.5=48.6 鬼x 弋.5=97.2x -M0.5 .5=97.2 0.5x=48.6(26)5X - 7.8=20.2 ,5x - 7.8+7.8=20.2+7.8 ,5x 弋=28 P,x=5.6 ;(27)2.5X - X=1.8 ,1.5

11、x 壬5=1.8 侥, x=1.2 ;(28)( 4.5+X) 2=13 ,(4.5+x) 吃=13 吃，4.5+x - 4.5=6.5 - 4.5,x=2 .(29)7x - 2X9=80 ,7x - 18=80,7x - 18+18=80+18 , 7x=98 ,7x T=98 , x=14 ;(30)13x - 7.5x=18.7 ,(13 - 7.5) x=18.7 ,5.5x=18.7,5.5x 55=18.7 5.5,x=3.4 ;(31)( x+12) 6=108,(x+12 ) 66=108 -6, x+12=18 ,x+12 - 12=18 - 12,x=6 .(32)4x+

12、3X0.7=6.54x+2.1=6.5 4x+2.1 - 2.1=6.5 - 2.1 4x=4.44x -4=4.4 x=1.1(33)2X (x - 0.5) =1.62x - 1=1.62x- 1 + 1=1.6+12x=2.62x -2=2.6 乞x=1.3(34)3x2.34=4.9147.02x=4.9147.02x 7.02=4.914 7t02x=0.7(35)1.44 -x=0.41.44 xk=0.4 X0.4x=1.440.4x 0.4=1.44 04x=3.6(36)2x+6=12.52x+6 - 6=12.5 - 62x -2=6.5 2 x=3.25 ;(37)2.5

13、x - x=1.21.5x=1.21.5x 1.5=1.2 侥x=0.8;(38)( 4.5+x) 2=63(4.5+x) X2 -2=63-2 4.5+x - 4.5=31.5 - 4.5 x=27;(39)2x - 2.5 0=152x - 25+25=15+252x -2=40 -2x=20 .(40)3.85+1.5x=6.13.85+1.5x=6.13.85 - 3.85+1.5x=6.1 - 3.851.5x=2.251.5x 1.5=2.25 15x=1.5(41)13 (x+2.5) =16913 (x+2.5) -13=169 -13x+2.5=13x+2.5 - 2.5=1

14、3 - 2.5x=11.5(42)2x - 2+1.8=3.62x - 0.2=3.62x+0.2 - 0.2=3.6+0.22x=3.82x -2=3.8 2x=1.9(43)7 ( x- 1.2) =3.577 (x - 1.2) T=3.57 子x- 1.2=0.51x+1.2 - 1.2=1.2+0.51x=1.71(44)2+1.8 - 2x=3.63.8- 2x+2x=3.6+2x3.8 3.6=3.6+2x 3.60.2 2=2x 吃x=0.1 ;(45)7xP.3=4.27x 电3 03=4.2 0.37x -7=1.26 7x=0.18 ;(46)6x+4x 11=32.91

15、0x 11 + 11=32.9+1110x -10=43.9 10x=4.39 ;(47)7 ( x 1.2) =2.877 (x 1.2) -7=2.87 7x 1.2+1.2=0.41+1.2 x=1.61(48)2.4+3.4x=5.8 2.4+3.4x 2.4=5.8 2.43.4x=3.43.4x 3.4=3.4 34x=1 ；(49)5 ( x 1.2) =355 (x 1.2) -5=35-5x 1.2=7x 1.2+1.2=7+1.2x=8.2;(50)2.5x+51=17 X82.5x+51=1362.5x+51 51=136 512.5x=852.5x 2.5=85 2.5

16、x=34 .(51)2.4x+1.6x=2.24x=2.24x -4=2.2 4(52)8 (x 6.2) =41.68 (x 6.2) -8=41.6 8x 6.2+6.2=5.2+6.2x=11.4 .(53)0.5 (x 0.5) =7.50.5 (x 0.5) -0.5=7.5 05x 0.5=15x 0.5+0.5=15+0.5 x=15.5;(54)( 9x+1.5+7x ) -5=5.1(16x+1.5) -5=5.1(16x+1.5) -5 X5=5.1 3 16x+1.5=25.5 16x+1.5 1.5=25.5 1.5 16x=2416x -16=24 -16 x=1.5

17、 ;(55)3x+7=29.53x+7 7=29.5 73x=22.53x -3=22.5 3x=7.5(56)5x 2.8 X.2=1.045x 3.36=1.045x 3.36+3.36=1.04+3.365x=4.45x -5=4.4 5x=0.88(57)4x+6x=28.510x=28.810x-10=28.5 10x=2.85(58)2.38x+9.8=33.6 2.38x+9.8 9.8=33.6 9.82.38x 2.38=23.8 238x=10(59)2 (x 3) =10.62(x 3) -2=10.6 2x 3+3=5.3+3x=8.3 ;(60)13x x=14.42

18、.7x - 1.8+1.8=1.2x+2.7+1.8 ,12x=14.412x 勻2=14.4 4-2x=1.2 ;(61)68 - 1.1x=2468 - 1.1x+1.1x=24+1.1x68 - 24=24+1.1x - 2444 .仁 1.1x 1.1 x=40.(62)3 ( x+3.5) =21.63(x+3.5) =21.6 4 x+3.5 3.5=7.2 3.5 x=3.7;(63)3x - 54=136.53x - 54+54=136.5+543x 43=190.5 3x=63.5 ;(64)x- 0.36x=3.20.64x=3.20.64x 0.64=3.2 064x=5

19、 ;(65)4x+2.8 4=19.324x+11.2 - 11.2=19.32 - 11.24x -4=8.12 4x=2.03 .(66)4x - 5.2=5.24x - 5.2+5.2=5.2+5.24x=10.44x -4=10.4 4x=2.6 ;(67)4.8x+2.6x=3.77.4x=3.77.4x 7.4=3.7 74x=0.5 ;(68)3x+6.4 2=50.33x+12.8=50.33x+12.8 - 12.8=50.3 - 12.83x=37.53x -3=37.5 3x=12.5 .(69)2.7x - 1.8=1.2x+2.7 ,2.7x - 1.2x=1.2x+

20、4.5 - 1.2x,1.5x 1.5=4.5 15,x=3 ;(70)8 - 5 (6x+0.7) =10x+0.5 ,8 - 30x - 3.5=10x+0.5 ,4.5- 30x+30x=10x+0.5+30x ,4.5- 0.5=40x - 0.5,4-40=40x -40,x=0.1 ;(71)7 -x- 0.7=1.3,7 -x- 0.7+0.7=1.3+0.7 ,7 -x ,7 -2=2x -2, x=3.5;(72)( 5.9+x) -3+16=30 ,(5.9+x) -3+16 - 16=30 - 16,(5.9+x) -3X3=14 X3,5.9+x - 5.9=42 -

21、5.9, x=36.1 .(73)0.56 X - 4x=0.4 ,2.8- 4x=0.4 ,2.8- 4x+4x=0.4+4x ,0.4+4x=2.8 ,0.4+4x - 0.4=2.8 - 0.4,4x=2.4 ,4x -4=2.4 -4,x=0.6 ;(74)4 (x - 0.5) =9.6 ,4x - 2=9.6 ,4x - 2+2=9.6+2 ,4x=11.6 ,4x -4=11.6 4,x=2.9 .(75)2X (x+1.7) =9.22 X (x+1.7)吃=9.2 -x+1.7=4.6x+1.7 - 1.7=4.6 - 1.7x=2.9 .(76)8x - 4x=0.644x

22、=0.644x -4=0.64 x=0.16.16.2,(77)2x - 0.24=0.122x - 0.24+0.24=0.12+0.242x=0.362x =0.36 舍 x=0.18 .(78)( 3.8 - 2) x=14.41.8x=14.41.8x 壬8=14.4 18x=8 .(79)64 - 16X=56.864 - 16X+16X=56.8+16X16X+56.8=6416X+56.8 - 56.8=64 - 56.816X=7.216X-16=7.2 46X=0.45 ;(80)8.6X - 2.6X=36.66X=36.66X -6=36.6 &X=6.1 ;(81)2.

23、2 (X+8 ) =222.2(X+8 ) 42.2=22 2.2X+8=10X+8 - 8=10 - 8X=2 ；(82)6X4 - 0.6X=6.3624 - 0.6X=6.3624 - 0.6X+0.6X=6.36+0.6X0.6X+6.36=240.6X+6.36 - 6.36=24 - 6.360.6X=17.640.6X -0.6=17.64 06X=29.4(83)0.03 X50 - 5x=3.24.5- 5x=3.2 ,4.5- 5x+5x=3.2+5x ,4.5- 3.2=3.2+5x - 3.2 ,1.3-5=5x 45, x=0.26 ;35.7+4X=45.3 ,35

24、.7+4X - 35.7=45.3 - 35.7,4X=9.6 ,4X-4=9.6 -4,X=2.4 ;(85)3 ( 5.4+X ) -6=7.2 ,(3X5.4+3X) 为 0=7.2 6,16.2+3X=43.2 ,16.2+3X - 16.2=43.2 -3X=27 ,3X-3=27 七，X=9 ;(86)5.9X+7=8.7X ,5.9X+7 - 7=8.7X - 7, 5.9X=8.7X - 7,5.9X - 5.9X=8.7X - 7 - 5.9X ,2.8X - 7=0,2.8X - 7+7=0+7 ,2.8X=7 ,2.8X -.8=7 -.8,X=2.5 .(87)3+0.6x=4.323+0.6x - 3=4.32 - 3,0.6x 4.6=1.32 0.6,x=2.2 ;(88)0.6 (y- 0.4) =6 ,0.6 (y- 0.4) -).6=6 4.6, y- 0.4+0.4=10+0.4 , y=10.4(84)45.3 - 4X=35.7 ,45.3- 4X+4X=35.7+4X ,