小数方程计算专项练习题

1、小数方程专项练习(有答案)15) 4( 0.3+x) =6.8(16) 8x- 1.6x=19.2(17) x-1.8=1.62(18) 22.5 X2+5x=135,(19) 1.4x+9.8=22.4 ，(20) 2 (x-3) =11.6,(21) 68-4.4x=24,(22) 1.6X8- 5x=2.3(23) 2.5x+20=16(24) 6.2x -x=41.6(25) x+0.5=48.6 X2(26) 5X- 7.8=20.2 ,(27) 2.5X X=1.8,(28) (4.5+X) X2=13,(1) (x+0.55 ) X 4=3.6(2) 2x+8=0.8(3) 1.

2、5X2+2x=5(4) 4) 4.7x=1.9x+7(5) 12.6 (x+4.8) +2=63(6) 6) 12.5+4x=21.7(7) 13.5x - 8.5x=20(8) 6x-8.5X4=20(9) 36+x=0.4(10) 9.6x -x=43(11) 3x-4X0.9=46.2(12) 3.5x -4X7=42(13) x- 0.9x=81.9( 14) 3.8+5x=12.3(29) 7x-2X9=80,(30) 13x-7.5x=18.7 ,(45) 7x+0.3=4.2(31) (x+12) X 6=108,(32) 4x+3X 0.7=6.5(33) 2X (x-0.5)

3、 =1.6(34) 3xX2.34=4.914(35) 1.44+x=0.436 2x+6=12.5(37) 2.5x -x=1.2(38) (4.5+x) X2=63(39) 2x-2.5 X 10=1540 3.85+1.5x=6.141 13( x+2.5=169(42) 2x- 2+1.8=3.6(43) 7 (x 1.2 ) =3.57(46) 6x+4x- 11=32.9(47) 7 (x- 1.2 ) =2.8748 2.4+3.4x=5.8(49) 5 (x- 1.2 ) =35(50) 2.5x+51=17X851 2.4x+1.6x=2.2(52 ) 8 (x-6.2 )

4、=41.6(53) 0.5 (x- 0.5 ) =7.5(54) (9x+1.5+7x) +5=5.1( 55 3x+7=29.5(56) 5x-2.8 X 1.2=1.0457 4x+6x=28.558 2.38x+9.8=33.6(44) 2+1.8 - 2x=3.6(59) 2 (x-3 ) =10.6(60) 13x-x=14.4(74) 4 (x-0.5 ) =9.6 ,(75) 2X ( x+1.7) =9.2(76) 8x - 4x=0.64(77) 2x- 0.24=0.12(78) ( 3.8 -2 ) x=14.4(79) 64- 16X=56.8(80) 8.6X - 2

5、.6X=36.6(82 ) 6X4- 0.6X=6.36(83) 0.03 X 150- 5x=3.2(84) 45.3 - 4X=35.7 ,(85) 3 (5.4+X) +6=7.2,86 5.9X+7=8.7X，87 3+0.6x=4.32(88) 0.6 (y 0.4 ) =6,小数方程88 题参考答案：(1) (x+0.55) X 4=3.6(61) 68- 1.1x=2462 3( x+3.5=21.6(63) 3x- 54=136.5(64) x- 0.36x=3.2(65) 4x+2.8 X 4=19.32(66) 4x - 5.2=5.267 4.8x+2.6x=3.7(68

6、) 3x+6.4 X 2=50.3(69) 2.7x - 1.8=1.2x+2.7 ,(70) 8-5 (6x+0.7 ) =10x+0.5 ,(71) 7 + x- 0.7=1.3 ,(72) (5.9+x) +3+16=30,(73) 0.56 X 5- 4x=0.4 ,(x+0.5 ) X4-4=3. 6-412.5+4X - 12.5=21.7 - 12.54x+4=9.2 +4x=2.3(7) 13.5x - 8.5x=205x-5=20-5x=4(8) 6x-8.5 X4=206x - 34=206x - 34+34=20+346x + 6=54+ 6x=9(9) 36-x=0.4

7、36-xXx=0.4 Xx36=0.4 Xx36-0.4=0.4 Xx-0.4x=90;(10) 9.6x - x=43(9.6 - 1) x=438.6x -8.6=43-8.5x=5;(11) 3x-4X0.9=46.23x - 3.6=46.23x - 3.6+3.6=46.2+3.6x+0.5=0.9x+0.5- 0.5=0.9 - 0.5x=0.4(2) 2x-8=0.82x-8X4=0.8 X4x=3.2(3) 1. 5X2+2x=53+2x=53+2x- 3=5- 32x + 2=2+2x=1(4) 4.7x=1.9x+74.7x - 1.9x=1.9x - 1.9x+72.8x

8、=72.8x -2.8=7-2.8x=2.5(5) 12.6 (x+4.8) -2=636.3 X ( x+4.8 ) =636.3 X ( x+4.8 ) -6.3=63-6.3x+4.8=10x+4.8- 4.8=10 - 4.8x=5.2:(6) 12.5+4x=21.73x-3=49.8-3x=16.6x=3(12) 3.5x -4X7=423.5x- 28=423.5x- 28+28=42+283.5x=703.5x +3.5=70 + 3.5 x=20;(13) x- 0.9x=81.90.1x=81.90.1x +0.1=81.9 +0.1x=819;(14) 3.8+5x=12

9、.33.8+5x - 3.8=12.3 - 3.85x=8.55x+5=8.5 + 5x=1.7;(15) 4 (0.3+x) =6.84 (0.3+x) +4=6.8+40.3+x=1.70.3+x- 0.3=1.7 - 0.3x=1.4(16) 8x- 1.6x=19.26.4x=19.2,(17) x-1.8=1.62x+1.8 X 1.8=1.62 X1.8 ,x=2.916;(18) 22.5 X2+5x=135,45+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,

10、1.4x +1.4=12.6 +1.4 , 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- 24,6.4x +6.4=19.2 +6.4 ,4.4x=44、4.4x +4.4=44 4-4.4 , x=10(22) 1.6X8- 5x=2.312.8 - 5x+5x=2.3+5x2.3+5x - 2.3=12.8 -2.3 5x+5=10. 5+5x=2

11、.1;(23) 2.5x+20=162.5x +20X20=16X 202.5x +2.5=320+2.5x=128;(24) 6.2x -x=41.65.2x=41.65.2x +5.2=41.6 +5.2x=8;(25) x+0.5=48.6 X2x + 0.5=97.2x + 0.5 X 0.5=97.2 X0.5x=48.6(26) 5X- 7.8=20.2 ,5x - 7.8+7.8=20.2+7.8 , 5x+5=28+ 5,x=5.6;(27) 2.5X X=1.8,1.5x +1.5=1.8 +1.5 , x=1.2;(28) (4.5+X) X2=13,(4.5+x) X 2

12、 + 2=13+ 2,4.5+x- 4.5=6.5 4.5,x=2(29) 7x-2X9=80,7x -18=80,7x-18+18=80+18,7x=98,7x+7=98+ 7, x=14;(30) 13x-7.5x=18.7 ,(13- 7.5 ) x=18.7 ,5.5x=18.7,5.5x +5.5=18.7 +5.5 ,x=3.4;(31) (x+12) X 6=108, (x+12) X 6-6=108-6, x+12=18,x+12- 12=18- 12,x=6(32) 4x+3X 0.7=6.54x+2.1=6.54x+2.1-2.1=6.5 -2.11.5x=1.24x=4.

13、44x + 4=4.4 +4x=1.1(33) 2X ( x- 0.5 ) =1.62x - 1 = 1.62x - 1+1=1.6+12x=2.62x+2=2.6+2x=1.3(34) 3xX2.34=4.9147.02x=4.9147.02x-7.02=4.914 +7.02x=0.7(35) 1.44+x=0.41.44 + xXx=0.4 Xx0.4x=1.440.4x +0.4=1.44 +0.4x=3.6(36) 2x+6=12.52x+6-6=12.5-62x+2=6.5+2x=3.25;1.5x +1.5=1.2 +1.5x=0.8;(38) (4.5+x) X2=63 (4.

14、5+x) X 2 + 2=63+2 4.5+x-4.5=31.5 -4.5x=27;(39) 2x-2.5 X 10=152x -25+25=15+25 2x+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 +1.5 x=1.5(41) 13 (x+2.5 ) =16913(x+2.5) +13=169+ 13x+2.5=13x+2.5-2.5=13 - 2.5x=11.5(42) 2x-2+1.8=3.6(37) 2.5x -x=1.22x0.2=3.62x

15、+0.2 0.2=3.6+0.2x1.2+1.2=0.41+1.22x=3.8 2x + 2=3.8+2x=1.9(43) 7 (x- 1.2 ) =3.577 (x- 1.2 ) +7=3.57+7x- 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+2x3.83.6=3.6+2x3.60.2 +2=2x+2x=0.1;(45) 7x+0.3=4.27x+0.3 X0.3=4.2 X0.37x+7=1.26+7x=0.18;(46) 6x+4x- 11=32.910x - 11+11=32.9+1110x+

16、10=43.9 + 10x=4.39;(47) 7 (x- 1.2 ) =2.87x=1.61(48) 2.4+3.4x=5.8(49) 3.4x-2.4=5.8 -2.43.4x=3.43.4x +3.4= 3.4 +3.4 x=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=17X82.5x+51=1362.5x+51 -51=136- 512.5x=852.5x +2.5=85+2.5x=34(51) 2.4x+1.6x=2.24x=2.24x+4=2.2+4x=0

17、.55;(52) 8 (x- 6.2 ) =41.67 (x- 1.2 ) +7=2.87+78 (x- 6.2 ) +8=41.6+8x-6.2+6.2=5.2+6.25x+5=4.4 + 5x=11.4(53) 0.5 (x-0.5) =7.5 0.5 (x-0.5 ) +0.5=7.5 +0.5x - 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) +5X5=5.1 X5 16x+1.5=25.516x+1.5- 1.5=25.5 -1.516x=2416x+16=24+

18、 16 x=1.5;(55) 3x+7=29.53x+7- 7=29.5 - 73x=22.5 3x+3=22.5+ 3x=7.5(56) 5x-2.8 X 1.2=1.045x - 3.36=1.045x -3.36+3.36=1.04+3.36x=0.88(57) 4x+6x=28.510x=28.810x+ 10=28.5 + 10x=2.85(58) 2.38x+9.8=33.62.38x+9.8- 9.8=33.6 - 9.82.38x+2.38 =23.8 + 2.38x=10(59) 2 (x- 3) =10.62 (x- 3) +2=10. 6 + 2x - 3+3=5.3+3

19、x=8.3;(60) 13x -x=14.412x=14.412x+12=14.4 + 12x=1.2;(61) 68- 1.1x=2468- 1.1x+1.1x=24+1.1x68-24=24+1.1x - 2444+1.1=1.1x +1.1x=405x=4.4(62) 3 (x+3.5) =21.63(x+3.5) +3=21.6+3(68) 3x+6.4 X 2=50.3x+3.5-3.5=7.2 - 3.5x=3.7;(63) 3x- 54=136.53x - 54+54=136.5+543x+3=190.5 + 3x=63.5;(64) x- 0.36x=3.20.64x=3.20

20、.64x-0.64=3.2 +0.64x=5;(65) 4x+2.8 X 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 +7.4x=0.5;3x+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- 1.8+1.8=

21、1.2x+2.7+1.8,2.7x- 1.2x=1.2x+4.5 T.2x ,1.5x +1.5=4.5 +1.5 ,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 + xXx=2Xx,7 + 2=2x+ 2, x=3.5;(72) (5.9+x) +3+16=30,(5.9+x ) +3+16- 16=30- 16

22、,(5.9+x) +3X3=14X 3,4x + 4=0.64+45.9+x- 5.9=42 - 5.9 ,x=36.1(73) 0.56 X 5- 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 ) =9.22X (x+1.7) -2=9.2-2 x+1.7=

23、4.6x+1.7- 1.7=4.6 -1.7x=2.9(76) 8x- 4x=0.64x=0.16(77) 2x-0.24=0.122x- 0.24+0.24=0.12+0.242x=0.362x+2=0.36+2x=0.18(78) (3.8 - 2) x=14.41.8x=14.41.8x + 1.8=14.4 +1.8x=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 + 16X=0.45;(80) 8.6X - 2.6X=36.66X=36.66X+ 6=36.6+6X=6.1;(81) 2.2 (X