数学人教版五年级上解方程ppt课件.ppt

解 方 程,4- , ,1 = 2 1把茶壶的重量2个茶杯的重量,1 + 1 = 2 + 1 1把茶壶的重量1个茶杯的重量2个茶杯的重量1个茶杯的重量, - 2 ,1 + 2 = 2 +2 1把茶壶的重量2个茶杯的重量2个茶杯的重量2个茶杯的重量, - 1 ,1 + 1 = 2 +1 1把茶壶的重量1个茶壶的重量2个茶杯的重量1个茶壶的重量, , .,1 = 2 , .等式的两边同时加上相等的数，等式不变。,1 + 1 = 2 + 1 ,1 + 2 = 2 +2 .,1 + 1 = 2 +1 ., 1 - ,1 ( ) .,3, ( ) .等式两边同时加上（或减去）相同的数，等式不变。, 1 - , 2 2 , 3 4 5 . ,1 , ( ) . 等式两边同时乘或除以相同的数（0除外），等式不变。,1. .,2. (0 ) ., , 解 方 程,4- , ,100g,100+x250,X=？,100+x, ,100g,100+x250,X=？,x=150 ,100+x-100=250-100,100+x250,x150,求方程的解的过程叫做解方程。, .使方程左右两边相等的未知数的值，叫做方程的解。, 100+x=250 x=150 . ,x = 6 , 6 ( / ) .,5 + x = 11 6 , .x = 6,6,11,=,X=3 5x=15 X=2 ,x=3 - ., :, =5x =53 =15 = x=3 ., x=2 5x=15 ., ,3x=12 (x=4 x=6 ),3.5- x=2.1 (x=3.8 x=1.4 ),0.7(x-2)=5.6 (x=8 x=10 ),(x+0.4)2.5=1 (x=2 x=2.1 ),!,X,9 ,x+3=9,x, .,x + 3 = 9 x=,- 3,- 3,6,x+3=9 .,x=6 .,x+3=9x+3-3=9-3 x=6, =x+3 =6+3 =9 = , x=6 ., 0 .,x,x,x,3x（ ）=18（ ）,3x=18 ., 0 .,x,x,x,3x（ ）=18（ ）,3,3,3x=18 .,3x=18,3x（ ）=18（ ）,3,3,x=6, !,: =3x =36 =18 = x=6 .,:, . (1) x 5 = 7 ; (2) 4x = 4 ；,x 5 +57+5,x12,:,:,4x 4 4 4,x1,1. .,2. ,x + 3.2 = 4.6 x 1.8 = 4 x 2 = 15 1.6 x = 6.4 x 7 = 0.3 x 3 = 2.1,8.4,4 , . 4x = 3x+4 ；,:,4x -3x 3x+4 -3x,x4, =4x =44 =16, x=4 .,:, =3x+4 =34+4 =124 =16, = , .,33x=65 33 + x - ( ) = 65 - ( ) X - 4.5 = 10 X - 4.5 ( ) = 10( ) 6x = 72 6x ( ) = 72 ( ) X 30 = 1.5 X 30 ( ) = 1.5 ( ),33,33,+ 4.5,+ 4.5, 6, 6,x 30,x 30, ,X,0.5,2.5,36, ., ., 28 ., x 40 , 5cm.,152cm,Y , 2.8 ., s .,a,25 3 ., ,14.14-0.64=13.5（m）, = + , 8 14.14m 0.64m . , : X :x+0.64=14.14x+0.64-0.64=14.14-0.64 x=13.5 . : 13.5, 1.17 6 徐虹身高1.17米，她比去年长高了6厘米，她去年身高多少？, 1.8kg ., = 30 , : x . 1.8kg=1800g 30 x=1800 30 x30=180030 x=60 : 60 ., 1.8kg ., 18 , / x, : x :45 :128 , 75g, ., .,a + 2 = 12 b + 3 = 12c + 4 = 12 d + 5 = 12,a - 2 = 12 b - 3 = 12c - 4 = 12 d - 5 = 12,a 2 = 12 b 3 = 12c 4 = 12 d 5 = 12,2a = 12 3b = 12 4c = 12 5d = 12, , 16 ., 689.75cm2 ., ., ？,!,